Interesting DS Question
This topic has expert replies
- dhanda.arun
- Senior | Next Rank: 100 Posts
- Posts: 52
- Joined: Thu Jul 31, 2008 12:30 pm
- Thanked: 5 times
- Morgoth
- Master | Next Rank: 500 Posts
- Posts: 316
- Joined: Mon Sep 22, 2008 12:04 am
- Thanked: 36 times
- Followed by:1 members
Question stem : is k square of an integer?
Statement (1)
k is divisible by 4
if k=4, k = 2^2, yes
if k=8, then k is not a square of an integer. Insufficient.
Statement (2)
k is divisible by 4 prime numbers
if k = 2^2 * 3^2 * 5^2 * 7^2 = yes k is square of an integer.
if k = 2*3*5*7 = no k is not a square of an integer. Insufficient.
Combining (1) & (2)
divisible by 4, exactly 4 different prime numbers
if k = 2^2 * 3^2 * 5^2 * 7^2- satisfies both the conditions and yes k is square of an integer.
if k = 2^2 * 3* 5 * 7 satisfies both the conditions and no k is not a square of an integer. Insufficient.
Thus, E is the answer.
Statement (1)
k is divisible by 4
if k=4, k = 2^2, yes
if k=8, then k is not a square of an integer. Insufficient.
Statement (2)
k is divisible by 4 prime numbers
if k = 2^2 * 3^2 * 5^2 * 7^2 = yes k is square of an integer.
if k = 2*3*5*7 = no k is not a square of an integer. Insufficient.
Combining (1) & (2)
divisible by 4, exactly 4 different prime numbers
if k = 2^2 * 3^2 * 5^2 * 7^2- satisfies both the conditions and yes k is square of an integer.
if k = 2^2 * 3* 5 * 7 satisfies both the conditions and no k is not a square of an integer. Insufficient.
Thus, E is the answer.