Question

A bag has 2 yellow, 7 red, and 1 green marble. What is the probability of picking a red marble, replacing it, and then picking a green marble?

Answer 1

Probability = number of ways an event can occur/total number of possible outcomes

To approach this question, you would first figure out the possibility of picking a red marble in the first draw, then multiply it by the possibility of picking a green marble in the second draw after you replaced the red marble.

So:
(number of red marbles/total number of marbles)*(number of green marbles/total number of marbles)