GMAT Set 6 Q13

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 110
Joined: Mon Feb 09, 2015 1:52 am
Followed by:4 members

GMAT Set 6 Q13

by Abhijit K » Thu Feb 19, 2015 12:45 am
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.

Is the answer C or E?

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Thu Feb 19, 2015 3:34 am
Is the number seconds required to travel d� feet at r� feet per second greater than the number of seconds required to travel d₂ feet at r₂ feet per second?

(1) d� is 30 greater than d₂
(2) r� is 30 greater than r₂
Clearly, neither statement alone is sufficient.

Statements combined:
Since d�=d₂+30 and r�=r₂+30, the question stem can be rephrased as follows:
Is (dâ‚‚ + 30)/(râ‚‚ + 30) > dâ‚‚/râ‚‚?

Case 1: dâ‚‚=1 and râ‚‚=1
(1+30)/(1+30) > 1/1
1 > 1.
NO.

Case 2: dâ‚‚=1 and râ‚‚=2
(1+30)/(2+30) > 1/2
31/32 > 1/2.
YES.

Since in the first case the answer is NO, but in the second case the answer is YES, INSUFFICIENT.

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3