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

Redeem

Some Q's

Expert replies
by Suyog » Wed Oct 03, 2007 3:52 pm
1. If r and s are integers, is r2 + s even ?
(1) The product rs is odd.
(2) r is odd.

2. What is the volume of a certain rectangular solid?
(1) Two adjacent faces of the solid have areas 15 and 24, respectively.
(2) Each of two opposite faces of the solid has area 40.
Join the discussion
Source: — Data Sufficiency |

by wongee » Wed Oct 03, 2007 5:07 pm
Type yes/No

St 1: Product rs is odd

so, try options or you should know:
Odd X Even = Even
Even X Even = even
Odd X Odd = Odd

If the product rs is odd, the only option is that both r and s are odd. Which now makes r2 + s = OddX2 + Odd = Even + Odd = Always Odd - SUFFICIENT Eliminate BCE

St II: r is odd.
So, r2 +s = Odd X 2 + s = Even +s
But s can be either odd or even giving either a odd or an even result. INSUFFICIENT

Answer Choice A What is the correct answer

Please correct me if I am wrong!
Join the discussion