If the probability that the product of the outcomes of three  rolls of a fair dice is a prime number p then the value of  3p is

Total number of cases n(S)=63=216Product is prime only when two outcomes are 1 and the third is prime i.e. 2,3,,5. If it is 2, 1, 1 then number of cases are 3 Similarly 3 cases, for 3, 1, 1 and 5, 1, 1 each Hence favorable cases = 9  Hence required probability p=124