DATA Sufficiency Probability

Expert replies

Robinmrtha: Senior | Next Rank: 100 Posts; Posts: 91; Joined: Wed Apr 01, 2009 9:53 pm; Thanked: 11 times

by Robinmrtha » Sun Jun 07, 2009 5:44 pm

A critical meeting on the subprime crisis has been scheduled. A group of investment bankers, whose mean age is 59, must attend. Each banker must flip a coin to choose whether to wear either a pinstripe suit or a solid suit. How many executive are attending the meeting?

1) The sum of their ages is a multiple of 3

2) The probability of all of the bankers wearing a solid suit is less than 1/3 and greater than 1/24

The answer is C how?

Like this post

Source: Beat The GMAT — Data Sufficiency | Sun Jun 07, 2009 5:44 pm

Claret: Senior | Next Rank: 100 Posts; Posts: 97; Joined: Sat Jun 06, 2009 10:48 pm; Thanked: 4 times

by Claret » Sun Jun 07, 2009 6:06 pm

statement 1 : Insufficient
this implies the no. of executives attending the meeting is a multiple of 3 i.e it cud be 3, 6, 9....

statement 2 : Insufficient

probability of an executive to wear a solid suit is 1/2
therefore probability of n executives to wear a solid suit = (1/2)^n
1/24<(1/2)^n<1/3

Statement 1 & 2 give
n = 3

therefore ANS C

Like this post

shashank.mehra: Junior | Next Rank: 30 Posts; Posts: 12; Joined: Mon Jun 15, 2009 8:59 pm

by shashank.mehra » Thu Jun 18, 2009 12:33 pm

Claret wrote:statement 1 : Insufficient
this implies the no. of executives attending the meeting is a multiple of 3 i.e it cud be 3, 6, 9....

statement 2 : Insufficient

probability of an executive to wear a solid suit is 1/2
therefore probability of n executives to wear a solid suit = (1/2)^n
1/24<(1/2)^n<1/3

Statement 1 & 2 give
n = 3

therefore ANS C

Pl elaborate on how can you deduce from Statement 1 that the number of Exec attending the conf is a multiple of three... even if four guys are attending the sum of their ages can be a multiple of 3.

Like this post

Claret: Senior | Next Rank: 100 Posts; Posts: 97; Joined: Sat Jun 06, 2009 10:48 pm; Thanked: 4 times

by Claret » Thu Jun 18, 2009 12:45 pm

ok..

it is given in the question stem that the mean of the ages of the executives is 59
sum of ages = no. of executives * mean age of the executives
from statement 1 :
sum of ages =(multiple of 3) *59
therefore we can conclude that the sum of the ages is a multiple of 3..

hope it helps..

Like this post

shashank.mehra: Junior | Next Rank: 30 Posts; Posts: 12; Joined: Mon Jun 15, 2009 8:59 pm

by shashank.mehra » Fri Jun 19, 2009 5:52 am

thanx man

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