efficient prblm please help

[curlydafatboy]

a motor furnishes 120 hp (746W=1hp) to a hoisting device that lifts 5000kg load to height of 13.0 meters in a time of 20.0 seconds. Find the efficiency....please help sum1 at least a formula?????[*(]

[Jimmy]

Energy = power * time. Figure out the ratio of the energy converted in lifting the 5000kg mass to the total energy that was used by the machine.