A desk drawer has 20 pens: 4 fountain pens 10 gel pens and 6 ballpoint pens. What is the probability of randomly choosing a gel pen replacing it and then choosing a fountain pen?

Answer 1

The probability of randomly choosing a gel pen first is 10/20 = 1/2.
After replacing the gel pen, there are now 20 pens remaining in the drawer, with 4 of them being fountain pens.
So, the probability of randomly choosing a fountain pen second is 4/20 = 1/5.

To find the overall probability of both events happening, we multiply the individual probabilities:
(1/2) * (1/5) = 1/10

Therefore, the probability of randomly choosing a gel pen and then a fountain pen is 1/10 or 0.1.