Question

A box contains 4 red pens,5 black pens, and 3 blue pens. If Robert selects one pen, and then another pen without putting the first pen back in the box, what is the probability that both pens will be black?

Answer 1

(p black) = 5/12

(p black) = 4/11

Explanation:

Add the pens together to find the total

4 + 5 + 3 = 12

Find the probability of drawing the first black pen.

(p black) = 5/12

The black pen is not replaced, so now there are 11 pens in the box, and there are only 4 black pens.

Find the probability of drawing the second black pen.

(p black) = 4/11