Question

Two number cubes whose sides are numbered 1 through 6 are rolled on a table. The two numbers showing are added. If you repeat this process 300 times, how many times would you expect the two cubes to add to exactly 7?

Answer 1

50 times

Explanation:

First we need to find the possible values that will make the sum 7:

(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)

There are 6 possible combinations among the 36 possible results (6 for each dice), so the probability of rolling a sum of 7 is 6/36 = 1/6

If we repeat the process 300 times, we could expect that the number of times that the sum will be 7 will be:

300 * (1/6) = 300/6 = 50 times