Which is not a prime number? (a) 13       (b) 19     (c) 21      (d) 17

Which is not a prime number? (a) 13 (b) 19quad (c)21, (d) 17

Which of the following is not a prime number? 21 (b) 23 (c) 29 (d) 43

The median of first 10 prime numbers is (a) 11 (b) 12 (c) 13 (d) 14

The median of first 10 prime numbers is (a) 11 (b) 12 (c) 13 (d) 14

Which of the following is an odd composite number? Options are (a) 13 (b) 17 (c) 12 (d) 15.

Which of the following is a prime number 19 (b) 20 (c) 21 (d) 22

The mean of a data is 15 and the sum of the observations is 195. The number of observations is (a) 13 (b) 19 (c) 16 (d) 17

Four prime numbers are arranged in ascending order. The product of first three is 385 and that of last three is 1001. The largest prime number is 9 (b) 11 (c) 13 (d) 17

The number of prime numbers between 0 and 50 is 14 (b) 15 (c) 16 (d) 17

Which of the following are not twin-primes? 3, 5 (b) 5, 7 (c) 11, 13 (d) 17, 23