Probability, number cubes

Question

Two number cubes are tossed, find the probability only one shows a 2

Answer 1

Well each cube has six numbers so possible combinations are 6 x 6 = 36

If one shows a cube we can have

2 1 2 3 2 4 2 5 2 6

1 2 3 2 4 2 5 2 6 2

So 10 ways

So probability = 10 / 36 = 5 / 18 (simplified)