Numbers - General Aptitude

Q1:

Which one of the following is a prime number ?

A 161

B 221

C 373

D 437

E None of these

ANS:C - 373

437 > 22 All prime numbers less than 22 are : 2, 3, 5, 7, 11, 13, 17, 19. 161 is divisible by 7, and 221 is divisible by 13. 373 is not divisible by any of the above prime numbers. 373 is prime.