A commuter drives from Mandaue to Bogo 120 km away at an average speed of 60 kph and returned to Mandaue at an average speed of 40 kph. What was the average speed of the commuter for the whole journey?

A commuter drives from Mandaue to Bogo 120 km away at an average speed of 60 kph and returned to Mandaue at an average speed of 40 kph. What was the average speed of the commuter for the whole journey?