Question

Larry rolls 2 fair dice and adds the results from each.

Work out the probability of getting a total of 8.

Answer 1

`Probability = (5)/(36)`

Explanation:

The samples are

{ ( 1 , 1) , ( 1 , 2 ) , ( 1 , 3 ) , ( 1 , 4 ) , ( 1 , 5) , ( 1 , 6 )

( 2 , 1 ) , ( 2 2 ) , ( 2 , 3 ) , ( 2 , 4 ) , ( 2 , 5 ) , ( 2 , 6 )

( 3 , 1 ) , ( 3 , 2 ) , ( 3 , 3 ) , ( 3 , 4 ) , ( 3 , 5 ) , ( 3 , 6 )

( 4 , 1 ) , ( 4 , 2 ) , ( 4 , 3 ) , ( 4 , 4 ) , ( 4 , 5 ) , ( 4 , 6 )

( 5 , 1 ) , ( 5 , 2 ) , ( 5 , 3 ) , ( 5 , 4 ) , ( 5 , 5 ) , ( 5 , 6 )

( 6 , 1 ) , ( 6 , 2 ) , ( 6 , 3 ) , ( 6 , 4 ) , ( 6 , 5 ) , ( 6 , 6 ) }

Total number of samples = 36

Samples with a sum of 8 = { ( 2 , 6 ) , ( 3 , 5 ) , ( 4 , 4 ) , ( 5 , 3 ) , ( 6 , 2 ) }

Total number of sample with sum 8 = 5

Therefore,

`Probability \ of \ sum \ of \ 8 = (5)/(36)`