NA

Correct Answer: 47

Explanation:

All others are complete squares.

Correct Answer: 6655

Explanation:

4867 ? 4 + 8 + 6 + 7 = 25, which is divisible by 5.
5555 ? 5 + 5 + 5 + 5 = 20, which is divisible by 5.
6243 ? 6 + 2 + 4 + 3 = 15, which is divisible by 5.
6655 ? 6 + 6 + 5 + 5 = 22, which is not divisible by 5.

Correct Answer: 18

Explanation:

All except '18' are square of natural numbers.
(5)² = 25, (3)² = 9, (4)² = 16

Correct Answer: OUT

Explanation:

All others have only one vowel.

Correct Answer: NPK

Explanation:

In all other groups, there is a gap of one letters as in the alphabet between first and third letters.

Correct Answer: 63

Explanation:

All others are prime numbers.

Correct Answer: 32

Explanation:

All others are divisible by 3.

Correct Answer: 96

Explanation:

All others have only 3 factors.
12 = 2 x 2 x 3, 28 = 2 x 2 x 7, 52 = 2 x 2 x 13
68 = 2 x 2 x 17, 96 = 2 x 2 x 2 x 2 x 2 x 3

Correct Answer: 72

Explanation:

All others have only 2 factors with prime number.
26 = 2 x 13, 34 = 2 x 17, 72 = 2 x 2 x 2 x 3 x 3,
46 = 2 x 23, 38 = 2 x 19

Correct Answer: 45

Explanation:

All others are prime numbers.