The probability that a prime number occurs on at least 2 tosses when a balanced dice is tossed 5 times independently is equal to

primes on a die are 2,3 and 5

so prob of a prime = 3/6 = 1/2
and prob NOT prime = 1-1/2= 1/2

prob of no prime = C(5,0) (1/2)^5 = 1/32
prob of one prime = C(5,1) (1/2)(1/2)^4 = 5/32

prob of at least 2 primes = 1 - 1/32 - 5/32 = 26/32 = 13/16 or .8125