find the probability that a number selected from numbers 1 , 2 , 3 , . . . , 20 is a prime number , when each of the given numbers is equally likely to be selected ?
"let x be the event of selecting a prime number . x = { 2 , 3 , 5 , 7 , 11 , 13 , 17 , 19 } n ( x ) = 8 , n ( s ) = 20 hence , the required probability is 8 / 20 . answer : c"
divide(multiply(3, const_5), 20)