Question

A box contains 500 marbles. The result of 20 marbles pulled at random from the box is given below.

• 5 red marbles
• 6 blue marbles
• 3 green marbles
• 4 black marbles
• 2 yellow marbles

Based on this information, how many black marbles could be expected in the box?

Answer 1

100 black marbles can be pulled

Answer 2

100 black marbles

Explanation:

The experimental probability of a black marble is

P(black) = 4/20 = 1/5

We expect that out of the 500 marbles in the box, 1/5 of them are black

1/5 (500) = 100

There should be 100 black marbles