Question

The diagram below shows all the possible totals from adding the results of rolling a two fair dice.

a) whats the probability of rolling a total of 5? give ur answer as a fraction in its simplest form.
b) if you rolled a pair of fair dice 180 times, how many times would you expect to roll a total of five?​

Answer 1

Expected number of times to roll a total of 5 = Probability of rolling a total of 5 x Total number of rolls

= (1/9) x 180

= 20

Explanation:

The diagram is not visible in the question. However, I can provide a general method to solve the problem.

a) To find the probability of rolling a total of 5, we need to count the number of ways we can get a sum of 5 and divide it by the total number of possible outcomes. From the diagram, we can see that there are four ways to get a sum of 5: (1,4), (2,3), (3,2), and (4,1). Since each die has six equally likely outcomes, there are 6 x 6 = 36 possible outcomes in total. Therefore, the probability of rolling a total of 5 is:

Probability of rolling a total of 5 = Number of ways to get a total of 5 / Total number of possible outcomes

= 4/36

= 1/9 (in its simplest form)

b) If we rolled a pair of fair dice 180 times, the expected number of times we would roll a total of 5 can be calculated as follows:

Expected number of times to roll a total of 5 = Probability of rolling a total of 5 x Total number of rolls

= (1/9) x 180

= 20