Question

While rolling two dice, what is the probability of rolling a sum of 7 or more? Select one: a. 1/6 b. 7/12 c. 5/9 d. 5/36

Answer 1

wo unbiased dice are rolled once,

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

n(S) = 36

Let A be an event a sum equal to 7

A= {(1,6),(2,5),(3,4),(4,3),(5,2),(6,1)}

n(A) = 6

P(A) = n(A)/n(S)

P(A) = 6/36

= 1/6

Ans : 1/6