Question

Chris wants to put six plants in a row on his windowsill. He randomly chooses each plant to be an aloe plant, a basil plant, or a violet. What is the probability that either exactly four of the plants are aloe plants or exactly five of the plants are basil plants?

Answer 1

Can Chris have four AND five plants? No. So we have to use casework to try to find out what the probability for having 4 aloe plants or 5 basil plants. Long story short, the math ends up as 24/243 = 8/81.