Question

A box contains 5 blue, 3 red and 2 white identical balls. If two balls are selected at random one after the other with replacement from the box, find the probability of selecting a) two blue or two red balls b) one red and one white ball

Answer 1

a) Probability of selecting two blue balls:
= (5/10) * (5/10) = 25/100 = 1/4

Probability of selecting two red balls:
= (3/10) * (3/10) = 9/100

Probability of selecting two blue or two red balls:
= Probability of selecting two blue balls + Probability of selecting two red balls
= 1/4 + 9/100
= 25/100 + 9/100
= 34/100
= 17/50

b) Probability of selecting one red and one white ball:
= (3/10) * (2/10) + (2/10) * (3/10)
= 6/100 + 6/100
= 12/100
= 3/25