Answer
The energy that is expended is $53,450~J$
Work Step by Step
We can find the increase in gravitational potential energy:
$mgh = (80.0~kg)(9.80~m/s^2)(15~m) = 11,760~J$
This work is 22% of the total energy expended by the muscles. We can find the total energy that was expended:
$0.22~E = 11,760~J$
$E = \frac{11,760~J}{0.22}$
$E = 53,450~J$
The energy that is expended is $53,450~J$.
