Bunuel wrote:
m and n are positive integers. If m/n and m+n both are even, which of the following must be odd?
I. (m+n)/2
II. (m+2)/2
III. (n+2)/2
A. I only
B. II only
C. III only
D. I and II only
E. II and IIIonly
Solution:
- m and n are positiveintegers
- It is given that\(m+n=even\) which means either\(m\) and\(n\) are both even or bothodd
- It is also given that\(\frac{m}{n}\) is even which means couple ofthings
- \(m\) and\(n\) are botheven (because odd/odd is noteven)
- \(m\) is even multiple of\(n\)
- Let us assume\(n=2k\) and\(m=2qn=4kq\) where k and q are positive integers
- Let us analyze each statement one byone
- (m+n)/2
- \(⇒\frac{4kq+2k}{2}=2kq+k=\) may or may not beodd
- (m+2)/2
- \(⇒\frac{4kq+2}{2}=2kq+1=even+1=\) alwaysodd
- (n+2)/2
- \(⇒\frac{2k+2}{2}=k+1=\) may or may not beodd
Hence the right answer is OptionB
...
Statistics : Posted by SaquibHGMATWhiz • on 02 Feb 2023, 08:50 • Replies 2 • Views 150









