Question

Two distingt number cubes, one red and one blue are rolled together. Each number cubes have sides numbered 1-6. What is the probability that the outcome is an odd sum or a sum that is a multiple of 5.

Answer 1

P(odd) or P(multiple of 5)

When we roll 2 number cubes all possible outcomes of their sum are 2,3,4,5,6,7,8,9,10,11,12.(11 possible outcomes)

Out of those possible outcomes

3,5,7,9,11 are odd (5 outcomes) and 5 and 10 are multiples of 5 (2 outcomes)

Now, P(odd) or P(multiple of 5) really means P(odd) + P (multiple of 5) =

(If we had “and” instead of “or” we multiply)

= (5/11) +(2/11)

=7/11

Hope this helps :p