GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 09 Dec 2018, 18:05

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • Free GMAT Algebra Webinar

     December 09, 2018

     December 09, 2018

     07:00 AM PST

     09:00 AM PST

    Attend this Free Algebra Webinar and learn how to master Inequalities and Absolute Value problems on GMAT.
  • Free lesson on number properties

     December 10, 2018

     December 10, 2018

     10:00 PM PST

     11:00 PM PST

    Practice the one most important Quant section - Integer properties, and rapidly improve your skills.

A migrating bird flew across a lake at an average speed of 18 meters p

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Current Student
User avatar
Joined: 12 Aug 2015
Posts: 286
Concentration: General Management, Operations
GMAT 1: 640 Q40 V37
GMAT 2: 650 Q43 V36
GMAT 3: 600 Q47 V27
GPA: 3.3
WE: Management Consulting (Consulting)
A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 16 May 2016, 22:12
2
23
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

66% (02:21) correct 34% (02:21) wrong based on 644 sessions

HideShow timer Statistics

A migrating bird flew across a lake at an average speed of 18 meters per second. Was the distance that the bird flew across the lake less than 21 kilometers? (1 kilometer = 1000 meters)

(1) It took the bird less than 20 minutes to fly across the lake.

(2) It took the bird less than 0.4 hour to fly across the lake.

_________________

KUDO me plenty

Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 7095
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 16 May 2016, 22:37
10
5
shasadou wrote:
A migrating bird flew across a lake at an average speed of 18 meters per second. Was the distance that the bird flew across the lake less than 21 kilometers? (1 kilometer = 1000 meters)

(1) It took the bird less than 20 minutes to fly across the lake.

(2) It took the bird less than 0.4 hour to fly across the lake.


Hi,
the moment we are given SPEED and asked for distance, and the choices are in TIME, CHANGE speed and distance in TIME...
At a speed of 18m per sec, the bird will travel 21 kms in 21000/18 secs = 7000/6 seconds or 1167 seconds..
When can we answer the Q-
A) If the time is less than 1167 secs, we can answer the Q as definite YES
B) If the time is greater than 1167 secs, we can answer the Q as definite NO..


lets see the statements



(1) It took the bird less than 20 minutes to fly across the lake.
20 minutes is 1200 secs...
so time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..

(2) It took the bird less than 0.4 hour to fly across the lake.
0.4hour = .4*60 *60 secs = 1440 secs..
we can take same example as in (1)..
again Insuff..

Combined..
the set of examples remain..
time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..
E
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

General Discussion
Manager
Manager
avatar
S
Joined: 13 Dec 2013
Posts: 156
Location: United States (NY)
Concentration: General Management, International Business
GMAT 1: 710 Q46 V41
GMAT 2: 720 Q48 V40
GPA: 4
WE: Consulting (Consulting)
Reviews Badge
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 17 Apr 2017, 19:21
1
shasadou wrote:
A migrating bird flew across a lake at an average speed of 18 meters per second. Was the distance that the bird flew across the lake less than 21 kilometers? (1 kilometer = 1000 meters)

(1) It took the bird less than 20 minutes to fly across the lake.

(2) It took the bird less than 0.4 hour to fly across the lake.



1) Distance covered in 20min = 18x60x20=21600. Therefore, distance is <21600. Insuff.
2) 0.4h = 24min, which allows for a greater distance than 1). Insuff.
1) and 2) Insuff. No new information from using both statements.
Intern
Intern
User avatar
S
Joined: 26 Oct 2016
Posts: 28
Premium Member
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 06 May 2017, 22:04
chetan2u wrote:
shasadou wrote:
A migrating bird flew across a lake at an average speed of 18 meters per second. Was the distance that the bird flew across the lake less than 21 kilometers? (1 kilometer = 1000 meters)

(1) It took the bird less than 20 minutes to fly across the lake.

(2) It took the bird less than 0.4 hour to fly across the lake.


Hi,
the moment we are given SPEED and asked for distance, and the choices are in TIME, CHANGE speed and distance in TIME...
At a speed of 18m per sec, the bird will travel 21 kms in 21000/18 secs = 7000/6 seconds or 1167 seconds..
When can we answer the Q-
A) If the time is less than 1167 secs, we can answer the Q as definite YES
B) If the time is greater than 1167 secs, we can answer the Q as definite NO..


lets see the statements



(1) It took the bird less than 20 minutes to fly across the lake.
20 minutes is 1200 secs...
so time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..

(2) It took the bird less than 0.4 hour to fly across the lake.
0.4hour = .4*60 *60 secs = 1440 secs..
we can take same example as in (1)..
again Insuff..

Combined..
the set of examples remain..
time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..
E



Can you let me know where I went wrong:
I converted Speed into Km/h so its 64.8 Km/h
Now according to first statement t<20 mins i.e less than 1/3 hrs or 0.33 hrs

Now If I calculate the distance taking the max cvalue say 0.32 * 64.8 its 20.7 which is less than 21 hence I marked A.
Manager
Manager
User avatar
S
Joined: 24 Jan 2017
Posts: 58
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 29 Jul 2017, 01:39
ezzo wrote:
chetan2u wrote:
shasadou wrote:
A migrating bird flew across a lake at an average speed of 18 meters per second. Was the distance that the bird flew across the lake less than 21 kilometers? (1 kilometer = 1000 meters)

(1) It took the bird less than 20 minutes to fly across the lake.

(2) It took the bird less than 0.4 hour to fly across the lake.


Hi,
the moment we are given SPEED and asked for distance, and the choices are in TIME, CHANGE speed and distance in TIME...
At a speed of 18m per sec, the bird will travel 21 kms in 21000/18 secs = 7000/6 seconds or 1167 seconds..
When can we answer the Q-
A) If the time is less than 1167 secs, we can answer the Q as definite YES
B) If the time is greater than 1167 secs, we can answer the Q as definite NO..


lets see the statements



(1) It took the bird less than 20 minutes to fly across the lake.
20 minutes is 1200 secs...
so time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..

(2) It took the bird less than 0.4 hour to fly across the lake.
0.4hour = .4*60 *60 secs = 1440 secs..
we can take same example as in (1)..
again Insuff..

Combined..
the set of examples remain..
time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..
E



Can you let me know where I went wrong:
I converted Speed into Km/h so its 64.8 Km/h
Now according to first statement t<20 mins i.e less than 1/3 hrs or 0.33 hrs

Now If I calculate the distance taking the max cvalue say 0.32 * 64.8 its 20.7 which is less than 21 hence I marked A.


Hi ezzo,
Statement 1 says that it took the bird less than 20 minutes(or 0.33hrs) to fly across the lake. The time could be 0.32 hours, or it could be 0.3299 hours.
If the time were 0.32 hours, as you have calculated, the distance is less than 21. However, if the time were 0.3299 hours, the distance is 21.38, which is more than 21km.
Manager
Manager
User avatar
S
Joined: 24 Jan 2017
Posts: 58
A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 29 Jul 2017, 01:52
1
In these kinds of questions, it is best to first calculate the required information to answer the question, and then compare this information with Statements 1 and 2.
For example, we are given:
s=18 m/s
and we want to find out if total distance is less than 21km.
d>21km or 21,000m

First, convert speed to m/min to make the information comparable to statements 1 and 2.
(18 m/s) (60 s/min) = 18*6 m/min

To calculate the time,
t> 21,000/(18*6) = (7*3*100)/(9*2*3*2) [FACTORING WILL BE EASIER THAN MULTIPLYING THEN EVENTUALLY DIVIDING)
t> 7*25/9
t>175/9
t>19.44

(1) It took the bird less than 20 minutes to fly across the lake.
t could be less than 19.44 or could be more than 19.44. INSUFFICIENT.

(2) It took the bird less than 0.4 hour to fly across the lake.
0.4 hour=24min. Again, t could be less than 19.44 or could be more than 19.44. INSUFFICIENT.


Statement b did not really bring new information as we already know from Statement 1 that t is less than 19.44.
Thus 1&2 INSUFFICIENT.
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 7095
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 29 Jul 2017, 02:11
ezzo wrote:
chetan2u wrote:
shasadou wrote:
A migrating bird flew across a lake at an average speed of 18 meters per second. Was the distance that the bird flew across the lake less than 21 kilometers? (1 kilometer = 1000 meters)

(1) It took the bird less than 20 minutes to fly across the lake.

(2) It took the bird less than 0.4 hour to fly across the lake.


Hi,
the moment we are given SPEED and asked for distance, and the choices are in TIME, CHANGE speed and distance in TIME...
At a speed of 18m per sec, the bird will travel 21 kms in 21000/18 secs = 7000/6 seconds or 1167 seconds..
When can we answer the Q-
A) If the time is less than 1167 secs, we can answer the Q as definite YES
B) If the time is greater than 1167 secs, we can answer the Q as definite NO..


lets see the statements



(1) It took the bird less than 20 minutes to fly across the lake.
20 minutes is 1200 secs...
so time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..

(2) It took the bird less than 0.4 hour to fly across the lake.
0.4hour = .4*60 *60 secs = 1440 secs..
we can take same example as in (1)..
again Insuff..

Combined..
the set of examples remain..
time can be 1180 , ans is NO
and if time is 1110, ans is YES..
Insuff..
E



Can you let me know where I went wrong:
I converted Speed into Km/h so its 64.8 Km/h
Now according to first statement t<20 mins i.e less than 1/3 hrs or 0.33 hrs

Now If I calculate the distance taking the max cvalue say 0.32 * 64.8 its 20.7 which is less than 21 hence I marked A.


hi dont complicate the calculations by taking decimals..
so t<20min or t<1/3..
thus d<t*speed or d< 64.8*1/3...d<21.6
so d can be 21.5 also and 10 also..
insuff

hope it helps
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Manager
Manager
User avatar
G
Joined: 21 Mar 2017
Posts: 141
Location: India
GMAT 1: 560 Q48 V20
WE: Other (Computer Software)
GMAT ToolKit User Premium Member Reviews Badge
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 26 Dec 2017, 09:52
Bunuel Do we have a separate question directory for this type of questions? atleast one such question comes in gmat always.
_________________

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
When nothing seem to help, I would go and look at a Stonecutter hammering away at his rock perhaps a hundred time without as much as a crack showing in it.
Yet at the hundred and first blow it would split in two.
And I knew it was not that blow that did it, But all that had gone Before
.

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51035
Re: A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 26 Dec 2017, 09:58
Prashant10692 wrote:
Bunuel Do we have a separate question directory for this type of questions? atleast one such question comes in gmat always.


16. Distance/Rate Problems



For more check below:
ALL YOU NEED FOR QUANT ! ! !
Ultimate GMAT Quantitative Megathread
Questions' Bank
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Senior Manager
Senior Manager
avatar
G
Joined: 02 Apr 2014
Posts: 474
GMAT 1: 700 Q50 V34
A migrating bird flew across a lake at an average speed of 18 meters p  [#permalink]

Show Tags

New post 21 Feb 2018, 13:24
Question: 18t < 21000
=> t < 21000/18 secs?
=> t < 7000/6 secs?
=> t < 7000/360 mins?
=> t < 19.x mins?

Statement 1: It took the bird less than 20 minutes to fly across the lake. => t < 20 mins => not suff
Statement 2: It took the bird less than 0.4 hour to fly across the lake. => t < 24 mins => not suff

combining 1 + 2, t < 20, but still insuff to answer, t < 19.x?=> (E)
GMAT Club Bot
A migrating bird flew across a lake at an average speed of 18 meters p &nbs [#permalink] 21 Feb 2018, 13:24
Display posts from previous: Sort by

A migrating bird flew across a lake at an average speed of 18 meters p

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.