Question

A professional cyclist rides a bicycle that is 92 percent efficient. For every 100 joules of energy he exerts as input work on the pedals, how many joules of output work are used to move the bicycle?

Answer 1

The bicycle is 92% efficient, meaning 92% of energy input is converted to useful (in this case kinetic) energy. Just find 92% (=0.92) of the given input. So:
100*0.92 = 92J