Answer:
11 PM
Step-by-step explanation:
Since bus is going at 48 and motorcyclist going at 72, the motorcyclist will catch up the bus by 72 - 48 = 24 miles an hour
Also, since motorcyclist left 4 hours after the bus, the bus is already ahead by 48 * 4 = 192 miles
So how long will the motorcylicst take to catch up 192 miles at 24 miles catch-up an hour?
192/24 = 8 hours
To find time:
Motorcylist started 4 hours after 11 AM, so his time of starting is 3PM. Then it will take him 8 hours, so that is 11PM
Hence, at 11pm he will catch up to the bus.