# Consider rolling two dice once. Calculate the probability of rolling a sum of 5 or an even sum.

## Solution :

Sample space of rolling two dice = 36

Now, Event of sum of 5 = { (1,4) (2,3) (3,2) (4,1) } = 4

$$\implies$$ probability of getting sum of 5 is 4/36 = 1/9

Now, Event of even sum = { (1,1) (1,3) (1,5) (2,2) (2,4) (2,6) (3,1) (3,3) (3,5) (4,2) (4,4) (4,6) (5,1) (5,3) (5,5) (6,2) (6,4) (6,6) } = 18

$$\implies$$ probability of getting even sum is 18/36 = 1/2

Hence, probability of  getting sum of  5 or even sum = 1/9 + 1/2

= 11/18

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