Question

A box contains 150 black pens and 50 red pens. Jose said the sum of the probability that a randomly selected pen will not be black and the probability that the pen will not be red is 1. Explain whether you agree.
THANK YOU!!

Answer 1

prob(red pen) = 50/200 = 1/4
prob(not red) = 3/4

prob(black pen) = 150/200) = 3/4
prob(not black) = 1/4

their sum = 3/4 + 1/4 = 1

Answer 2

The answer is yes because the probability of the red pen is 25 percent(1/4). The percentage of the not red is 75 percent(3/4). The probability of the black pen is 75 percent(3/4). The probability of the not black is 25 percent(1/4). If you add these together you get 1, which is what Jose said. Therefore, the answer is yes.

Answer 3

answer
1/4