Oct 14 08:00 PM PDT  11:00 PM PDT Join a 4day FREE online boot camp to kick off your GMAT preparation and get you into your dream bschool in R2.**Limited for the first 99 registrants. Register today! Oct 15 12:00 PM PDT  01:00 PM PDT Join this live GMAT class with GMAT Ninja to learn to conquer your fears of long, kooky GMAT questions. Oct 16 08:00 PM PDT  09:00 PM PDT EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299) Oct 19 07:00 AM PDT  09:00 AM PDT Does GMAT RC seem like an uphill battle? eGMAT is conducting a free webinar to help you learn reading strategies that can enable you to solve 700+ level RC questions with at least 90% accuracy in less than 10 days. Sat., Oct 19th at 7 am PDT Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score.
Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 02 Dec 2012
Posts: 173

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
06 Dec 2012, 07:46
Question Stats:
62% (01:51) correct 38% (01:44) wrong based on 1773 sessions
HideShow timer Statistics
Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second? (1) d1 is 30 greater than d2 (2) r1 is 30 greater than r2.
Official Answer and Stats are available only to registered users. Register/ Login.




Math Expert
Joined: 02 Sep 2009
Posts: 58320

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
06 Dec 2012, 07:50
Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?We need to find whether \(\frac{d_1}{r_1}>\frac{d_2}{r_2}\). (1) d1 is 30 greater than d2 > \(d_1=d_2+30\). Nothing about the rates. Not sufficient. (2) r1 is 30 greater than r2 > \(r_1=r_2+30\). Nothing about the distances. Not sufficient. (1)+(2) The question becomes whether \(\frac{d_2+30}{r_2+30}>\frac{d_2}{r_2}\). Now, if \(d_2=r_2\), then \(\frac{d_2+30}{r_2+30}=\frac{d_2}{r_2}\), thus in this case the answer would be NO but if \(d_2=1\) and \(r_2=2\), then in this case \(\frac{d_2+30}{r_2+30}=\frac{31}{32}>\frac{1}{2}=\frac{d_2}{r_2}\), thus in this case the answer would be YES. Not sufficient. Answer: E. Generally if \(a\), \(b\) and \(c\) are positive numbers and \(a>b\) then \(\frac{a}{b}>\frac{a+c}{b+c}\) (\(\frac{a+c}{b+c}\) is closer to 1 then \(\frac{a}{b}\), but as \(\frac{a}{b}>1\) then \(\frac{a+c}{b+c}\) is getting less to be closer to 1). For example: \(\frac{3}{2}>\frac{3+30}{2+30}\); But if \(a\), \(b\) and \(c\) are positive numbers and \(a<b\) then \(\frac{a}{b}<\frac{a+c}{b+c}\) (again \(\frac{a+c}{b+c}\) is closer to 1 then \(\frac{a}{b}\), but as \(\frac{a}{b}<1\) then \(\frac{a+c}{b+c}\) is getting bigger to be closer to 1). For example: \(\frac{4}{5}<\frac{4+30}{5+30}\). Hope it's clear.
_________________




Director
Joined: 25 Apr 2012
Posts: 661
Location: India
GPA: 3.21
WE: Business Development (Other)

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
18 Dec 2012, 06:35
Walkabout wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2 (2) r1 is 30 greater than r2. Hi, St1 and st 2 alone are not sufficient so combining we get IS (d2+30)/(r2+30) > d2/r2 The asnwer to this Question will depend upon the ratio of d2/r2. If d2/r2 is <1, then on adding the same + ve qty to Num & Den will increase the ratio value if d2/r2 is > 1 ,then on adding the same qty will decrease the ratio Hence ans E
_________________
“If you can't fly then run, if you can't run then walk, if you can't walk then crawl, but whatever you do you have to keep moving forward.”




Intern
Joined: 20 Jan 2013
Posts: 27
Location: United Arab Emirates
WE: Engineering (Consulting)

Distance and Speed  Question 90 from OG13
[#permalink]
Show Tags
31 Jan 2013, 10:20
Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second? (1) d1 is 30 greater than d2. (2) r1 is 30 greater than r2. Now, when I solved this question, I was surprised to see that the solution was (E), i.e, none of the statements provide sufficient information. I recall, however, that when you add the same number to both the numerator and denominator of a fraction, the resulting fraction is always closer to 1. Using that logic, statements (1) and (2) TOGETHER provide sufficient information. Am I approaching this wrong here? EDIT: Okay, figured it out. The information regarding which number is bigger (the speed or the distance) is not provided. Which means that the new fraction (r2 and d2) could actually be approaching 1 from either 0 or from infinity. Clever.



Manager
Joined: 27 Jan 2013
Posts: 238
GMAT 1: 780 Q49 V51 GMAT 2: 770 Q49 V47 GMAT 3: 760 Q47 V48

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
Updated on: 19 Jul 2016, 14:40
Hi Absar, As with all DS: translating the given information is critical So the real question is: D1/R1 > D2/R2? (1) D1 = D2 + 30 You can substitute one of the variables. BUT R1 and R2 could be anything so you could answer yes by making R1 very tiny number and R2 a huge number or you could do the opposite and the answer would be no. Insufficient. (2) R1 = R2+ 30 The same logic as a above for this statement (1) + (2) If you put the statements together the question becomes: D2+30/R2+30 > D2/R2 You should test very big values and very small values to see what happens. If R2 is a very tiny value and D2 is a massive value then the left side will be smaller than the right side because R2 will be increased by a much greater factor than will D2. D2 = 1000 > 1030/31 > 1000/1 NO R2 = 1 And viceversa, if DS is a tiny value and R2 is a massive value than the left side will be greater because D2 will have a greater percentage increase than R2. D2 = 1 > 31/1030 > 1/1000 YES R2 = 1000So, you are able to say Yes and No to the original question so the the answer is E Let me know if you have any questions on this! HG.
_________________
"It is a curious property of research activity that after the problem has been solved the solution seems obvious. This is true not only for those who have not previously been acquainted with the problem, but also for those who have worked over it for years." Dr. Edwin LandGMAT vs GRE ComparisonIf you found my post useful KUDOS are much appreciated. IMPROVE YOUR READING COMPREHENSION with the ECONOMIST READING COMPREHENSION CHALLENGE:Here is the first set along with some strategies for approaching this work: http://gmatclub.com/forum/theeconomistreadingcomprehensionchallenge151479.html
Originally posted by AtlanticGMAT on 31 Jan 2013, 10:44.
Last edited by AtlanticGMAT on 19 Jul 2016, 14:40, edited 2 times in total.



Intern
Joined: 14 Jan 2013
Posts: 22
Location: India

Is the number of seconds required to travel d1 feet at r1 feet p
[#permalink]
Show Tags
15 May 2013, 23:41
kapilnegi wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2. questions is t1 > t2? or (d1/r1) > (d2 / r2)? => (d2 + 30)/(r2 + 30) > (d2/r2)? => [[(d2+30)(r2+30)]/(r2 + 30)] > (d2r2)/r2  subtract 1 on both sides => [(d2r2)/(r2+30)]>(d2r2)/r2 => 1/(r2+30) > 1/(r2) => (r2+30) < r2 => 30 < 0 ? This questions IMO is not answerable but justified in OG . Any thoughts? Am I wrong?



Intern
Joined: 05 Mar 2013
Posts: 41
Location: India
Concentration: Entrepreneurship, Marketing
GMAT Date: 06052013
GPA: 3.2

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
16 May 2013, 01:29
kapilnegi wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2. This problem depends on the following concept. If a,b are two positive numbers. and k is any positive number a. if a/b is greater than 1 then a+k/b+k is less than a/b b. if a/b is less than 1 then a+k/b+k is greater than a/b Now consider the Above question we have d1/r1 and d2/r2. but d1 = d2 + 30 r1 = r2 + 30 so we have d2+30/r2 + 30 and d2/r2 but we don't know whether d2 is greater than r2. So together these statements are not sufficient
_________________
"Kudos" will help me a lot!!!!!!Please donate some!!!
Completed Official Quant Review OG  Quant
In Progress Official Verbal Review OG 13th ed MGMAT IR AWA Structure
Yet to do 100 700+ SC questions MR Verbal MR Quant
Verbal is a ghost. Cant find head and tail of it.



Senior Manager
Joined: 13 May 2013
Posts: 405

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
30 Jul 2013, 15:50
Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
Time = distance/rate
t1>t2?
(1) d1 is 30 greater than d2
We know nothing about the rate for r1 and r2. INSUFFICIENT
(2) r1 is 30 greater than r2.
We know nothing about the distance of 1 an 2. Even if r1 is greater, the distance for 2 may be proportionally less so that even at a slower speed, d2 is covered in less time than d1. INSUFFICIENT
1+2)
Hypothetical A:
1: Distance = 31 feet and rate = 31 feet/second 2: Distance = 1 feet and rate = 1 foot/second
In this case the time it takes for both is the same.
Hypothetical B:
1: Distance = 330 feet and rate = 60 feet/second Time = Distance / Rate Time = 330 / 60 Time = 11/3 seconds
2: Distance = 300 feet and rate = 30 feet/second Time = Distance/Rate Time = 300 / 30 Time = 10 seconds
It's possible that the time to cover d1 is the same as d2. It also may be greater. INSUFFICIENT
(E)



Senior Manager
Joined: 01 Nov 2013
Posts: 283
WE: General Management (Energy and Utilities)

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
07 Mar 2015, 09:36
kiranck007 wrote: kapilnegi wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2. questions is t1 > t2? or (d1/r1) > (d2 / r2)? => (d2 + 30)/(r2 + 30) > (d2/r2)? => [[(d2+30)(r2+30)]/(r2 + 30)] > (d2r2)/r2  subtract 1 on both sides => [(d2r2)/(r2+30)]>(d2r2)/r2 => 1/(r2+30) > 1/(r2) => (r2+30) < r2 => 30 < 0 ? This questions IMO is not answerable but justified in OG . Any thoughts? Am I wrong? Can someone verify the above cited approach for this particular DS question?
_________________
Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time.
I hated every minute of training, but I said, 'Don't quit. Suffer now and live the rest of your life as a champion.Mohammad Ali



Math Expert
Joined: 02 Aug 2009
Posts: 7954

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
07 Mar 2015, 10:17
samichange wrote: kiranck007 wrote: kapilnegi wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2. questions is t1 > t2? or (d1/r1) > (d2 / r2)? => (d2 + 30)/(r2 + 30) > (d2/r2)? => [[(d2+30)(r2+30)]/(r2 + 30)] > (d2r2)/r2  subtract 1 on both sides => [(d2r2)/(r2+30)]>(d2r2)/r2=> 1/(r2+30) > 1/(r2) => (r2+30) < r2 => 30 < 0 ? This questions IMO is not answerable but justified in OG . Any thoughts? Am I wrong? Can someone verify the above cited approach for this particular DS question? hi samichange, this kind of approach is not required, it will just complicate the matters .. take each statement separately and then combined to see if they satisfy the answer... i think the approach was to show that the question is not justified as after simplifying it gives 30<0, which is not possible ... however the person has gone wrong after the colored portion... u just cant cancel d2r2 from each side.. you have to get the entire thing on one side and take d2r2 as common term outside..
_________________



Intern
Joined: 23 Jul 2013
Posts: 14

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
12 Jun 2015, 19:21
Bunuel wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
We need to find whether \(\frac{d_1}{r_1}>\frac{d_2}{r_2}\).
(1) d1 is 30 greater than d2 > \(d_1=d_2+30\). Nothing about the rates. Not sufficient. (2) r1 is 30 greater than r2 > \(r_1=r_2+30\). Nothing about the distances. Not sufficient.
(1)+(2) The question becomes whether \(\frac{d_2+30}{r_2+30}>\frac{d_2}{r_2}\). Now, if \(d_2=r_2\), then \(\frac{d_2+30}{r_2+30}=\frac{d_2}{r_2}\), thus in this case the answer would be NO but if \(d_2=1\) and \(r_2=2\), then in this case \(\frac{d_2+30}{r_2+30}=\frac{31}{32}>\frac{1}{2}=\frac{d_2}{r_2}\), thus in this case the answer would be YES. Not sufficient.
Answer: E. Hi Bunuel, I got the correct answer. However, i just pondered over this and found the below. Can you help me find out where am i wrong over here? D2 + 30 / r2 + 30 > d2/r2 ( combining the 2 statements) Now, r2(d2 +30) > d2(r2 +30) r2d2 + 30r2 > d2r2 + 30d2 r2 > d2 Then 2 st are sufficient together right?



Senior Manager
Joined: 10 Mar 2013
Posts: 467
Location: Germany
Concentration: Finance, Entrepreneurship
GPA: 3.88
WE: Information Technology (Consulting)

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
16 Nov 2015, 02:09
Walkabout wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2 (2) r1 is 30 greater than r2. I would rather simplify this expression further to derive at the answer: \(\frac{d2+30}{r2+30} > \frac{d2}{r2}\) > \(r2*d2+30*r2 > d2*r2 + 30*d2\), r2d2 cancel out and we have 30*r2 > 30*d2, if r2=d2 the answer is no, and if r2 > d2 the answer is yes, thus Answer (E)
_________________
When you’re up, your friends know who you are. When you’re down, you know who your friends are.
Share some Kudos, if my posts help you. Thank you !
800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50 GMAT PREP 670 MGMAT CAT 630 KAPLAN CAT 660



Manager
Joined: 17 Nov 2013
Posts: 77

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
02 Apr 2016, 15:34
R1T1 =D1 AND R2T2 =D2 => THE QUESTION ASKS IF THE TIME FOR 1 IS FASTER THAN FOR 2. SO FORMULA ALONE YOU CAN SAY \(T1 = \frac{D1}{R1}\), \(T2 = \frac{D2}{R2}\)
STMT1 SAYS THAT D1> D2 AND IF I PUT THAT INTO THE FORMULA I AM NOT SURE WHAT THE Rs ARE FOR ME TO CONFIRM WHICH ONE IF GREATER. INSUFFICIENT.
STMT2 SAYS THAT R1>R2 AND SIMILAR TO STMT1 I DONT HAVE ENOUGH INFORMATION TO CONFIRM.
COMBINING TOGETHER WE KNOW THAT D1>D2 AND R1>R2, AND OUR FORMULA OF \(\frac{D1}{R1} > \frac{D2}{R2}\) BUT WHAT WE KNOW ABOUT THESE VALUES DOES NOT HELP BECAUSE D1>D2 HELPS THE LEFT SIDE OF OUR EQUATION TO BE BIGGER WHILE R1>R2 HELPS THE RIGHT SIDE OF THE EQUATION TO BE BIGGER. WITHOUT KNOWING MORE NUMBERS I CANNOT SUFFICIENTLY. ANSWER E.



Intern
Joined: 11 Nov 2014
Posts: 32
Concentration: Marketing, Finance
WE: Programming (Computer Software)

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
08 May 2016, 13:47
time to travel d1 at r1 speed = d1/r1 time to travel d2 at r2 speed = d2/r2
is d1/r1 > d2/r2 ??
from (1) d1 = d2+30 not sufficient from (2) r1 = r2+30 not sufficient
now from (1) + (2) is (d2+ 30)/(r2+30) > d2/r2
first lets take d2 = 1 and r2 = 2 31/32 > 1/2 holds true but if d2 = 2 and r2 = 1 32/31 < 2/1 does nt hold true.
so correct option is E .



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2817

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
10 May 2016, 07:39
Walkabout wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2 (2) r1 is 30 greater than r2. Solution: We need to determine whether the number of seconds required to travel d_1 feet at r_1 feet per second is greater than the number of seconds required to travel d_2 feet at r_2 feet per second. We can set this question up in the form of an inequality. Remember that: time = distance/rate Thus, we can now ask: Is d_1/r_1 > d_2/r_2 ? When we cross multiply we obtain: Is (d_1)(r_2) > (d_2)(r_1) ? Statement One Alone:d_1 is 30 greater than d_2. From statement one, we can create the following equation: d_1 = 30 + d_2 Since d_1 = 30 + d_2, we can substitute 30 + d_2 in for d_1 in the inequality (d_1)(r_2) > (d_2)(r_1): Is (30 + d_2)(r_2) > (d_2)(r_1) ? We see that we still cannot answer the question. Statement one alone is not sufficient to answer the question. We can eliminate answer choices A and D. Statement Two Alone:r_1 is 30 greater than r_2. From statement two we can create the following equation: r_1 = 30 + r_2 Since r_1 = 30 + r_2, we can substitute 30 + r_2 for r_1 in the inequality (d_1)(r_2) > (d_2)(r_1): Is (d_1)(r_2) > (d_2)(30 + r_2) ? We see that we still cannot answer the question. Statement two alone is not sufficient to answer the question. We can eliminate answer choice B. Statements One and Two Together:Using the information from statements one and two we have the following equations: 1) d_1 = 30 + d_2 2) r_1 = 30 + r_2 Since d_1 = 30 + d_2 and since r_1 = 30 + r_2, we can substitute 30 + d_2 for d_1 and 30 + r_2 for r_1 in the inequality (d_1)(r_2) > (d_2)(r_1): Is (30 + d_2)(r_2) > (d_2)(30 + r_2) ? Is (30)(r_2) + (d_2)(r_2) > (30)(d_2) + (d_2)(r_2) ? Is (30)(r_2) > (30)(d_2) ? Is r_2 > d_2 ? Since we cannot determine whether r_2 is greater than d_2, statements one and two together are not sufficient to answer the question. The answer is E.
_________________
5star rated online GMAT quant self study course See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews
If you find one of my posts helpful, please take a moment to click on the "Kudos" button.



Manager
Joined: 12 Jun 2016
Posts: 212
Location: India
Concentration: Technology, Leadership
WE: Sales (Telecommunications)

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
03 Aug 2017, 08:11
Clearly S1 and S2 are insufficient by themselves. The Key thing here is to make the right judgement on S1+S2. What this question is really testing is our understanding of  what happens when the Numerator and denominator of a fraction is increased by a fixed number? To really hammer this concept and others related to it, do not forget to read this excellent post by Bunuel/MIKE McGARRY  https://gmatclub.com/forum/gmatshortcu ... l#p1856037I hope you find the above link useful
_________________



Manager
Joined: 27 Dec 2016
Posts: 227
Concentration: Marketing, Social Entrepreneurship
GPA: 3.65
WE: Marketing (Education)

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
03 Sep 2017, 09:58
Bunuel wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
We need to find whether \(\frac{d_1}{r_1}>\frac{d_2}{r_2}\).
(1) d1 is 30 greater than d2 > \(d_1=d_2+30\). Nothing about the rates. Not sufficient. (2) r1 is 30 greater than r2 > \(r_1=r_2+30\). Nothing about the distances. Not sufficient.
(1)+(2) The question becomes whether \(\frac{d_2+30}{r_2+30}>\frac{d_2}{r_2}\). Now, if \(d_2=r_2\), then \(\frac{d_2+30}{r_2+30}=\frac{d_2}{r_2}\), thus in this case the answer would be NO but if \(d_2=1\) and \(r_2=2\), then in this case \(\frac{d_2+30}{r_2+30}=\frac{31}{32}>\frac{1}{2}=\frac{d_2}{r_2}\), thus in this case the answer would be YES. Not sufficient.
Answer: E. Bunuel, Since d2 and r2 both are positive integers, we can multiply the latest inequality : \(\frac{(30+d2)}{(30+r2)} > \frac{d2}{r2}\) > \(30*r2 + d2*r2 > 30*d2 + d2*r2\). Thus we can eliminate \(d2*r2\) on the both side, we get : \(30r2>30d2\) > \(r2>d2\). With this inequality, your first test case : r2=d2 should not apply and this bring me to the C answer. What is wrong with my approach?
_________________
There's an app for that  Steve Jobs.



Math Expert
Joined: 02 Sep 2009
Posts: 58320

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
03 Sep 2017, 10:06
septwibowo wrote: Bunuel wrote: Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
We need to find whether \(\frac{d_1}{r_1}>\frac{d_2}{r_2}\).
(1) d1 is 30 greater than d2 > \(d_1=d_2+30\). Nothing about the rates. Not sufficient. (2) r1 is 30 greater than r2 > \(r_1=r_2+30\). Nothing about the distances. Not sufficient.
(1)+(2) The question becomes whether \(\frac{d_2+30}{r_2+30}>\frac{d_2}{r_2}\). Now, if \(d_2=r_2\), then \(\frac{d_2+30}{r_2+30}=\frac{d_2}{r_2}\), thus in this case the answer would be NO but if \(d_2=1\) and \(r_2=2\), then in this case \(\frac{d_2+30}{r_2+30}=\frac{31}{32}>\frac{1}{2}=\frac{d_2}{r_2}\), thus in this case the answer would be YES. Not sufficient.
Answer: E. Bunuel, Since d2 and r2 both are positive integers, we can multiply the latest inequality : \(\frac{(30+d2)}{(30+r2)} > \frac{d2}{r2}\) > \(30*r2 + d2*r2 > 30*d2 + d2*r2\). Thus we can eliminate \(d2*r2\) on the both side, we get : \(30r2>30d2\) > \(r2>d2\). With this inequality, your first test case : r2=d2 should not apply and this bring me to the C answer. What is wrong with my approach? The question becomes whether \(\frac{d_2+30}{r_2+30}>\frac{d_2}{r_2}\) or whether \(r_2>d_2\). If \(d_2=r_2\), the answer would be NO If \(d_2=1\) and \(r_2=2\), the answer would be YES.
_________________



Intern
Joined: 06 Oct 2015
Posts: 4

Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
30 Oct 2018, 10:32
Why are we not considering negative rates in this problem? Bunuel



Senior Manager
Status: Gathering chakra
Joined: 05 Feb 2018
Posts: 433

Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
Show Tags
15 May 2019, 17:57
Nothing says d2 can't be 0.
Say d2=0 and r2=2, thus the time2 is 0 d1=30,r1=32, thus the time1 is about .9, YES
Now say d2=10 and r2=2, time2 is 5 d1=40,r1=32, time1 is 1.25, NO
Statements are still insufficient together.




Re: Is the number of seconds required to travel d1 feet at r1
[#permalink]
15 May 2019, 17:57






