Two standard dice are rolled. The product of the two numbers rolled is calculated. What is the probability that the ones digit of this product is 0?

Question

Given Options

(A) 11/36

(B) 2/9

(C) 1/36

(D) 1/6

(E) 5/36

I am looking for answer + explanation.

Answer 1

6 possible outcomes making the answer 1/6

Answer 2

If you create a 6 x 6 matrix (each die can be a 1, 2, 3, 4, 5 or 6) there will be 6 x 6, or 36 possible product outcomes when you do the cross-multiplications of the rows x columns.

The products that end in 0 are:

2 x 5

4 x 5

5 x 2, 5 x 4, 5 x 6

6 x 5

6 possible outcomes end in a 0, so the probability is 6/36, or 1/6.