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

 It is currently 20 Sep 2018, 05:51

### 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

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

# What is the distance between Harry s home and his office?

Author Message
TAGS:

### Hide Tags

Director
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 505
Location: United Kingdom
GMAT 1: 730 Q49 V45
GPA: 2.9
WE: Information Technology (Consulting)
What is the distance between Harry s home and his office?  [#permalink]

### Show Tags

10 Nov 2011, 16:50
2
10
00:00

Difficulty:

15% (low)

Question Stats:

78% (00:46) correct 22% (00:37) wrong based on 578 sessions

### HideShow timer Statistics

What is the distance between Harry’s home and his office?

(1) Harry’s average speed on his commute to work this Monday was 30 miles per hour.
(2) If Harry’s average speed on his commute to work this Monday had been twice as fast, his trip would have been 15 minutes shorter.

Can someone please explain whether I have done it correctly or not?

Let d - distance between Harry's home and office
r - Rate
t - time

Considering Statement 1

Rate = Distance/Time
Distance = Rate * Time i.e D = 30 t. We can't calculate D unless we know t. Therefore, insufficient.

Considering Statement 2 on its own is clearly insufficient.

Considering both Statements together

If the speed remains 30mph then time will be 30 minutes { Is his correct?}

Therefore, D = r*t = 30 * 30/60 = 15 miles. Therefore, C is the right answer.

_________________

Best Regards,
E.

MGMAT 1 --> 530
MGMAT 2--> 640
MGMAT 3 ---> 610
GMAT ==> 730

Senior Manager
Joined: 11 May 2011
Posts: 342
Re: Distance between office and work - Ivy Q17  [#permalink]

### Show Tags

10 Nov 2011, 18:09
enigma123 wrote:
What is the distance between Harry’s home and his office?
(1) Harry’s average speed on his commute to work this Monday was 30 miles per hour.
(2) If Harry’s average speed on his commute to work this Monday had been twice as fast, his trip would have been 15 minutes shorter.

Can someone please explain whether I have done it correctly or not?

Let d - distance between Harry's home and office
r - Rate
t - time

Considering Statement 1

Rate = Distance/Time
Distance = Rate * Time i.e D = 30 t. We can't calculate D unless we know t. Therefore, insufficient.

Considering Statement 2 on its own is clearly insufficient.

Considering both Statements together

If the speed remains 30mph then time will be 30 minutes { Is his correct?}

Therefore, D = r*t = 30 * 30/60 = 15 miles. Therefore, C is the right answer.

If the speed remains 30mph then time will be 30 minutes - Absolutely Correct!!!!
D = r*t = 30 * 30/60 = 15 miles. - Method of solving this problem is correct.

Cheers!
_________________

-----------------------------------------------------------------------------------------
What you do TODAY is important because you're exchanging a day of your life for it!
-----------------------------------------------------------------------------------------

Manager
Joined: 25 Nov 2011
Posts: 214
Location: India
Concentration: Technology, General Management
GPA: 3.95
WE: Information Technology (Computer Software)
Re: What is the distance between Harry s home and his office?  [#permalink]

### Show Tags

08 Feb 2012, 06:45
1
Agree with C.

As per the second statement, if he had traveled twice the speed, he would have saved half of the time. Combining this with the first statement, we come to know half of the time is 15 min and hence total or actual time would be 30min. Now we know speed and time and hence we can calculate distance.
_________________

-------------------------
-Aravind Chembeti

Intern
Joined: 19 Apr 2012
Posts: 10
Concentration: Technology, General Management
GMAT Date: 06-26-2014
GPA: 4
WE: Programming (Computer Software)
Re: What is the distance between Harry s home and his office?  [#permalink]

### Show Tags

15 Feb 2014, 10:03
3
Though a long method for DS, but solved it as

Distance between home and office = d

I) Speed s= 30mph.
No other info provided, hence Insufficient

II) Original Speed = s
Original Time = t
New Speed = 2s
New Time = (t-0.25) [15 mins = 0.25hrs)

Distance is same, hence

s*t = 2s(t-0.25)
Solving results in t=0.5 hrs.

No info about speed hence, Insufficient.

I&II ) s= 30mph
t= 0.5hrs
d= s*t => 15miles. Ans: C
CEO
Joined: 12 Sep 2015
Posts: 2856
Re: What is the distance between Harry s home and his office?  [#permalink]

### Show Tags

03 Apr 2018, 10:08
Top Contributor
enigma123 wrote:
What is the distance between Harry’s home and his office?

(1) Harry’s average speed on his commute to work this Monday was 30 miles per hour.
(2) If Harry’s average speed on his commute to work this Monday had been twice as fast, his trip would have been 15 minutes shorter.

Let d = distance between Harry’s home and his office

Target question: What is the distance between Harry’s home and his office?

Statement 1: Harry’s average speed on his commute to work this Monday was 30 miles per hour.
To determine the distance (d), we need the travel time.
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: If Harry’s average speed on his commute to work this Monday had been twice as fast, his trip would have been 15 minutes shorter.
Travel time = (distance)/(speed)
Let v = Monday's speed,

(Monday's travel time) = (travel time at twice Monday's speed) + 15 minutes
Or..., (Monday's travel time) = (travel time at twice Monday's speed) + 0.25 hours
So, we can write d/v = d/2v + 0.25
Multiply both sides by 2v to get: 2d = d + 0.5v
Simplify: d = 0.5v
Divide both sides by v to get: d/v = 0.5
NOTE: distance/speed = time [in other words, time = d/v]
So, the Monday's travel time = 0.5 hours
So, statement 2 allows us to determine Monday's travel time, but we don't know Harry's speed.
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Statement 1 tells us that Harry's speed was 30 mph
Statement 2 tells us that Harry drove for 0.5 hours
Distance = (speed)(time)
So, distance = (30)(0.5) = 15 miles
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Cheers,
Brent
_________________

Brent Hanneson – GMATPrepNow.com

GMATH Teacher
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 175
Re: What is the distance between Harry s home and his office?  [#permalink]

### Show Tags

07 Sep 2018, 08:22
enigma123 wrote:
What is the distance between Harry’s home and his office?

(1) Harry’s average speed on his commute to work this Monday was 30 miles per hour.
(2) If Harry’s average speed on his commute to work this Monday had been twice as fast, his trip would have been 15 minutes shorter.

Excellent opportunity to practice UNITS CONTROL and BIFURCATION, two of our most powerful tools!

$$? = d\,\,\,\,\left[ {{\text{miles}}} \right]$$

$$\left( 1 \right)\,\,\,V = 30\,\,{\text{mph}}\,\,\,\left\{ \begin{gathered} \,{\text{Take}}\,\,\,{\text{T = }}\,\,{\text{1}}\,\,{\text{h}}\,\,\,\, \Rightarrow \,\,\,\,{\text{?}}\,\,{\text{ = }}\,\,{\text{30}}\,\, \hfill \\ \,{\text{Take}}\,\,\,{\text{T = }}\,\,2\,\,{\text{h}}\,\,\,\, \Rightarrow \,\,\,\,{\text{?}}\,\,{\text{ = }}\,\,60\,\,\, \hfill \\ \end{gathered} \right.\,\,\,\left[ {{\text{miles}}} \right]$$

$$\left( 2 \right)\,\,\,\,\frac{{d \cdot \boxed2}}{{V \cdot \boxed2}}\, - \frac{d}{{2V}}\,\,\,\,\,\mathop = \limits^{\left( * \right)} \,\,\,\,\frac{1}{4}\,\,\,\,\left[ {\text{h}} \right]\,\,\,\,\,\, \Rightarrow \,\,\,\,\underleftrightarrow {\frac{d}{{2V}} = \frac{1}{4}}\,\,\,\,\,\, \Rightarrow \,\,\,\,V = 2d\,\,\,\left( {**} \right)$$

$$\left( * \right)\,\,\,\frac{{\left[ {{\text{miles}}} \right]}}{{\left[ {{\text{mph}}} \right]}} = \left[ {\text{h}} \right]$$

$$\left\{ \begin{gathered} \,{\text{Take}}\,\,\,V = 2\,{\text{mph}}\,\,\,\,\mathop \Rightarrow \limits^{\left( {**} \right)} \,\,\,\,\,{\text{d = }}\,\,{\text{1}}\,\,{\text{mile}}\,\,\,\,\left( {T = 0.5\,\,{\text{h}}} \right)\,\,\,\,::\,\,\,\,{\text{viable!}}\,\,\,\,\, \hfill \\ \,\,{\text{Take}}\,\,\,V = 4\,{\text{mph}}\,\,\,\,\mathop \Rightarrow \limits^{\left( {**} \right)} \,\,\,\,\,{\text{d = }}\,\,{\text{2}}\,\,{\text{miles}}\,\,\,\,\left( {T = 0.5\,\,{\text{h}}} \right)\,\,\,\,::\,\,\,\,{\text{viable!}}\,\,\,\, \hfill \\ \end{gathered} \right.$$

$$\left( {1 + 2} \right)\,\,\,\,V = 30\,{\text{mph}}\,\,\,\,\mathop \Rightarrow \limits^{\left( {**} \right)} \,\,\,\,\,\boxed{{\text{d = }}\,\,{\text{15}}\,\,{\text{miles}}}\,\,\,\,\,\,$$

This solution follows the notations and rationale taught in the GMATH method.

Regards,
fskilnik.
_________________

Fabio Skilnik :: http://www.GMATH.net (Math for the GMAT)
Course release PROMO : finish our test drive till 30/Sep with (at least) 60 correct answers out of 92 (12-questions Mock included) to gain a 70% discount!

Re: What is the distance between Harry s home and his office? &nbs [#permalink] 07 Sep 2018, 08:22
Display posts from previous: Sort by

# Events & Promotions

 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®.