A man left home a 12 noon to go for a cycle ride. the man stopped for another rest at 2 pm. He rested for one hour. Then he cycled home at a steady speed. It took him 2 hours. What was his average speed on the way back home(NOT for the entire journey).

A1500 w electric heater is plugged into the outlet of a 120 v circuit that has a 20 a circuit breaker. you plug an electric hair dryer into the same outlet. the hair dryer has power settings of 600 w, 900 w , 1200 w, and 1500 w. you start with the hair dryer on the 600 w setting and increase the power setting until the circuit breaker trips. under what setting does the circuit breaker trip.