boys in the community

Expert replies

sanju09: GMAT Instructor; Posts: 3650; Joined: Wed Jan 21, 2009 4:27 amFollowed by: 80 members; Location: India; Thanked: 267 times; GMAT Score:760

by sanju09 » Wed Apr 15, 2009 4:40 am

In a community comprising of only boys and girls, the sum of ages of girls is 17 more than the sum of that of boys. What is the minimum possible number of boys in the community?

(1) The average (arithmetic mean) age of boys is 11 more than that of girls.

(2) The average (arithmetic mean) age of boys is 16.

MBM

The mind is everything. What you think you become. -Lord Buddha

Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com

Like this post

Source: Beat The GMAT — Data Sufficiency | Wed Apr 15, 2009 4:40 am

Vemuri: Legendary Member; Posts: 682; Joined: Fri Jan 16, 2009 2:40 amFollowed by: 1 member; Thanked: 32 times

Re: boys in the community

by Vemuri » Wed Apr 15, 2009 9:51 am

Let G be the sum of ages of girls & B be the sum of ages of boys. The question statment says that G-B=17

Stmt 1: B/x - G/y = 11 (where 'x' is the number of boys & 'y' is the number of girls). Does not help.

Stmt 2: B/x = 16. Is not sufficient by itself.

Combining Stmt 1 & 2, G/y=5. Does not help either.

My answer is E.

Like this post

vittalgmat: Legendary Member; Posts: 621; Joined: Wed Apr 09, 2008 7:13 pmFollowed by: 4 members; Thanked: 33 times

by vittalgmat » Wed Apr 15, 2009 12:45 pm

Very interesting one!!!!.

Great Job Sanju. keep it coming!!!>

I got C as the answer.
number of boys = 3 and number of girls = 13.

If this is correct, I will post the xplanation.

Like this post

mals24: Legendary Member; Posts: 683; Joined: Tue Jul 22, 2008 1:58 pmFollowed by: 2 members; Location: Dubai; Thanked: 73 times

by mals24 » Wed Apr 15, 2009 2:18 pm

Gosh really cool question Sanju

One more vote for C.

G: sum of ages of girls
g: number of girls
B: sum of ages of boys
b: number of boys

Given: G = 17+B

St1. B/b = G/g+11
St2. B/b = 16

Combining 1 and 2

16 = G/g + 11
G/g = 5
G =5g

B = 16b

5g = 17 + 16b

Now we need to find a minimum value.
Plug in values for b

When b = 0, 1 and 2
g will not be an integer.

Only when b = 3, g will be 13.

So the minimum value for b=3

Like this post

vittalgmat: Legendary Member; Posts: 621; Joined: Wed Apr 09, 2008 7:13 pmFollowed by: 4 members; Thanked: 33 times

by vittalgmat » Wed Apr 15, 2009 9:13 pm

Thanks Mals for the excellent explanation.
I went thru the same path!!!, and took more than 2 mins

to
arrive at the answer.

I think this is a 700 level question.
What do u guys think ?

rgds
-V

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