Question

Jimmy rolls a pair of dice. What is the probability that the numbers that show on the two dice add up to a prime number?

Answer 1

well, first we need to identify what probibilities we are looking for. since the sum of the dice are between 2 and 12 inclusively, the prime numbers we care about are 2,3,5,7,11.
for it to add up to 2 we have only 1 way, for 3 and 11 we have 2 ways to roll these combinations each: 1+2, 2+1, 5+6, 6+5. for 5 and 7 there are many ways. for 5 we have 1+4,2+3,3+2,4+1. For 7 we have 1+6,2+5,3+4,4+3,5+2,6+1. add up all these ways for all 6 numbers and we have 15 ways our of our total 36 ways to roll the pair of dice so our final probabilty is 15/36

Answer 2

thanks

Answer 3

no problem (:

Answer 4

15/36