6 of the 30 pens are green, so the probability of selecting a green pen is 6/30 = 1/5.
The pen is then replaced, so there are still 30 pens in the drawer. 4 of the pens are black, so the probability of selecting a black pen is 4/30 = 2/15.
The probability of both events is therefore 1/5 × 2/15 = 2/75.
