Question

What is the probability of getting sum 3 or 4 when 2 dice are rolled?

Answer 1

Total number of outcomes on rolling 2 dice = 6^2 = 36.

1) There are only 2 different ways of getting a sum of 3. 

 1 + 2 = 3.

2 + 1 = 3.


2) There are only 3 different ways of getting a sum of 4.

1 + 3 = 4

3 + 1 = 4

2 + 2 = 4.


The probability of getting the sum of 3 or 4 =  2 + 3/36

                         = 5/36.


Hope this helps!

Answer 2

total cases=36
favourable cases=(1,2); (1,3); (2,1); (2,2); (3,1)
P (sum 3 or 4)=no. of favourable cases / total no.of cases
=5/36