The times between the arrivals of taxis at a rank are independent and identically exponentially distributed with parameter λ = 4 [h −1 ]. Assume that an arriving customer does not find an available...

The times between the arrivals of taxis at a rank are independent and identically exponentially distributed with parameter λ = 4 [h⁻¹]. Assume that an arriving customer does not find an available taxi, the previous one left 3 minutes ago, and no other customers are waiting. What is the probability that the customer has to wait at least 5 minutes for the next free taxi?