Answer: 1/6
Step-by-step explanation:
Red pens = 3
Green pens = 2
Blue pen = 1
Total = 3+2+1 = 6
Probability of picking a red pen = 3/6 = 1/2
Probability of picking a green pen = 2/6 = 1/3
The probability of picking a red pen, replacing it, and then picking a green pen will be calculated as:
= 1/2 × 1/3
= 1/6