Problem Solving

Expert replies

rnaah: Junior | Next Rank: 30 Posts; Posts: 24; Joined: Thu Jul 15, 2010 9:45 am; Thanked: 1 times

by rnaah » Thu Sep 29, 2011 7:07 am

When water is poured on "cuscus" (a special food stuff of the Arabs), it doubles its size in its container every minute. If it takes 30 minutes for this soaked cuscus to fill its container, in which minute will the container be 1/16th full?

Like this post

Source: Beat The GMAT — Problem Solving | Thu Sep 29, 2011 7:07 am

GMAT/MBA Expert

Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members; Location: Vancouver, BC; Thanked: 5254 times; GMAT Score:770

by Brent@GMATPrepNow » Thu Sep 29, 2011 7:10 am

rnaah wrote:When water is poured on "cuscus" (a special food stuff of the Arabs), it doubles its size in its container every minute. If it takes 30 minutes for this soaked cuscus to fill its container, in which minute will the container be 1/16th full?

Time : Fraction filled
30 minutes : 1 (full)
29 minutes : 1/2 full
28 minutes : 1/4 full
27 minutes : 1/8 full
26 minutes : 1/16 full

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

Like this post

CappyAA: Master | Next Rank: 500 Posts; Posts: 124; Joined: Mon Jun 16, 2008 11:07 amFollowed by: 14 members; Thanked: 21 times; GMAT Score:750

by CappyAA » Thu Sep 29, 2011 7:13 am

You know the cuscus doubles in size every minute. So start at 30 minutes and work backwards.

At 30 minutes, the container is full. At 29 minutes, the container is 1/2 full. At 28 minutes, the container is 1/4 full. At 27 minutes, the container is 1/8 full. At 26 minutes, the container is 1/16 full.

Taking the GMAT Again...PhD this time!

October 2008 Score: GMAT - 750 (50 Q, 41 V)

Manhattan GMAT 1 - 11/20/11 - 750 (50 Q, 42 V)
Manhattan GMAT 2 - 12/3/11 - 780 (51 Q, 45 V)

Like this post

rohit_gmat: Master | Next Rank: 500 Posts; Posts: 158; Joined: Wed Jun 16, 2010 8:21 amFollowed by: 1 member; Thanked: 13 times

by rohit_gmat » Thu Sep 29, 2011 7:35 am

rnaah wrote:When water is poured on "cuscus" (a special food stuff of the Arabs), it doubles its size in its container every minute. If it takes 30 minutes for this soaked cuscus to fill its container, in which minute will the container be 1/16th full?

factor = 2 (double)
times = 30 (mins)

2^(30) => full container
(2^30))/(1/16) = 2^30/2^4 = 2^26

26 mins ...
but of course countin backwards is much easier n faster n clearer but i did it the other way

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review