O.G 12 PS 89

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

This topic has expert replies

Post new topic Post Reply

Previous Topic Next Topic

ssmiles08: Master | Next Rank: 500 Posts; Posts: 472; Joined: Sun Mar 29, 2009 6:54 pm; Thanked: 56 times

O.G 12 PS 89

by ssmiles08 » Wed May 13, 2009 6:53 pm

Can someone please help me out with this following problem. I have an Idea but don't really understand the solution given by the book. It's been a long day! Thanks in advance!

If s is the product of the integers 100 to 200 inclusive and t is the product of integers from 100 to 201 inclusive, what is 1/s +1/t in terms of t?

(A) (201)^2/t

(B) [(202)(201)]/t

(C) (201)/t

(D) 202/t

(E) [(202)(201)]/t^2

OA : D

Quote

Source: Beat The GMAT — Problem Solving | Wed May 13, 2009 6:53 pm

syr: Senior | Next Rank: 100 Posts; Posts: 38; Joined: Fri Feb 20, 2009 8:45 am; Thanked: 5 times

Solution

by syr » Wed May 13, 2009 7:53 pm

Here you go ..

s = 100 * 101 * .... * 200
t = 100 * 101 * .... * 200 * 201
i.e t = s * 201

Therefore, s = t/201
Also, 1/s = 201/t

Hence,
1/s + 1/t
= 201/t + 1/t
= 202/t

Hope that helps.

Thanks,
syr

Quote

Pranay: Senior | Next Rank: 100 Posts; Posts: 59; Joined: Tue May 05, 2009 1:58 am; Thanked: 1 times

Re: O.G 12 PS 89

by Pranay » Thu May 14, 2009 2:17 am

Hi Syr,

Great solution.

Hi ssmiles08,

Its been long time since I am looking for an OG12.

Could you please let me know the source for it. It would be great if you can share incase you have a soft copy of it.

My E-Mail is - [email protected]

It would be really helpful.

Pranay.