A bag contains 50 coins and each coin marked from 51 to 100. One coin is
picked up at random. The probability that the number on the coin is not a prime
number is
Total number of coins = 50
∴ Total number of outcomes = 50
prime numbers are 53, 59, 61, 67, 71, 73, 79, 83, 89, 97
P(prime numbers) = 
∴ P(not prime numbers) = 1 - 
= 