Question

probability of getting a sum less than 5 when two dice are rolled?

Answer 1

When two dice are rolled,

Sample space, S = {(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,)(5,3)(5,4)(5,5)(5,6)

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

So, n(S)= 36

Let "A" be the event of getting sum less than 5 on the dice.

Then A = {(1,1)(1,2)(1,3)(2,1)(2,2)(3,1)}

So, n(A)=6

So, P(A) = n(A)/n(S)= 6/36=1/6