Question

An experiment consists of rolling two fair number cubes. What is the probability that the sum of the two numbers will

be 8? Express your answer as a fraction in simplest form.

Answer 1

Probability of an event happening = Number of ways it can happen / Total number of outcomes ;
2 + 6 = 8; {2,6}
3 + 5 = 8 ; {3,5}
4 + 4 = 8 ; {4,4}
5 + 3 = 8 ; {5,3}
6 + 2 = 8 ; {6,2}
There are 5 number of ways it can can happen;
{1,1} {1,2} {1,3} {1,4} ... {6,3} {6,4} {6,5} {6,6}
There are 36 number of outcomes;
The probability is 5 / 36 = 0.138