There are 5 red pens and 10 black pens in a cup. If a person randomly selects 3 of them, what is the probability that they're all the same color? A. 0.286 B. 0.18 C. 0.264 D. 0.379
Accepted Solution
A:
Answer:option a) 0.286Step-by-step explanation:Given that, number of red pens in cup = 5 number of black pens in cup = 10 number of pen randomly selected = 3There are 5 red pens and 10 black pens. So there are 5 + 10 = 15 pens in all.probability of having all red pens = (5/15 x 4/14 x 3/13) = 2/91probability of having all black pens = (10/15 x 9/14 x 8/13) = 24/91 probability that all pen are of same colour = 24/91 + 2/91 = 2/7 ≈ 0.286