Question

Every cereal box has a gift inside, but you cannot tell from the outside what the gift is. The store manager assures you that 18 of the 52 boxes on the shelf have the secret decoder ring. The other 34 boxes on the shelf have a different gift inside. If you randomly select two boxes of cereal from the shelf to purchase, what is the probability that BOTH of them have the secret decoder ring?

Answer 1

3/26

Explanation:

Probability of the first box to have the secret decoder ring is 18 out of 52:

• 18/52= 9/26

Probability of the second box to have the ring is 17 out of 51, because one box with the ring already selected and not counted:

• 17/51= 1/3

Probability that both of them have the secret decoder ring:

• 9/26*1/3= 3/26

So the answer is 3/26