Question

Find the odd one out in the given options.

• A. $145$
• B. $197$
• C. $257$
• D. $325$
• E. $399$

Answer 1

The correct option is E $399$

$145=144={12}^2+1$

Similarly,

$197=196+1={14}^2+1$

$257=256+1={16}^2+1$

$325=324+1={18}^2+1$

But,

$399=400-1={20}^2-1$

Hence, E is the correct option.