Answer:
option a)
0.286
Explanation:
Given that,
number of red pens in cup = 5
number of black pens in cup = 10
number of pen randomly selected = 3
There 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)
= 2/91
probability 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