Question

What is the probability of picking a red marble after a blue marble had been picked first.

Answer 1

Answer:

Given the only two events that are possible in this example (picking a red marble or picking a blue marble), if you don't do the first, then you must do the second. That is, given this example, the probability of picking a red marble plus the probability of picking a blue marble will equal 1 (or 100 percent).