A real estate agent has 8 master keys to open several new homes. Only 1 master key will open any given house.

A real estate agent has 8 master keys to open several new homes. Only 1 master key will open anygiven house. If 40% of these homes are usually left unlocked, what is the probability that the real estate agentcan get into a speci¯c home if the agent selects 3 master keys at random before leaving the o±ce?