Question

A bag contains 10 red marbles, 15 yellow marbles, 5 green marbles, and 20 blue marbles. Two marbles are drawn from the

Answer 1

Answer:

•            (₁₀C₁) × (₂₀C₁)      

                           ₅₀C₂

Explanation:

There are a total number of 10 + 15 + 5 + 20 = 50 marbles.

The number of ways in which any two marbles can be drawn is the combination of 50 marbles taken two at a time: ₅₀C₂, since the order does not matter.

There are 10 red marbles and 20 blue marbles.

Thus, the combinations with one red marble are: ₁₀C₁.

The combinations with one blue marble are: ₂₀C₁.

The combinations with one red and one blue marble is the product of the previous two:

• ₁₀C₁ × ₂₀C₁

Thus, the probability that one of the marbles is read and the other is blue is the quotient of the two sets:

•            (₁₀C₁) × (₂₀C₁)      

                           ₅₀C₂