The waiter can serve 60 guests in 5 hours.To find how many he can serve in 5 hours, Let's first get how many he can serve in an hour.If he can serve 36 guests in 3 hours, we just divide 36 by 3.36 ÷ 3 = 12Now that we know that he can serve 12 guests per hour, we multiply that by 512 x 5 = 60Therefore, he can serve 60 guests in 5 hours.