Answer
$\approx 1.67 \times 10^{4} ft-lb$
Work Step by Step
The magnitude of the gravitational force acting on the man plus the can of paint is equal to $=160+25=185lbs$
Since we are moving in the upward direction:
$F \cdot dr=185 dr$
Work done: $W=\int_C F\cdot dr=185 \int_C dr$
Since $C$ shows a vertical line segment connecting the bottom and top of the silo, we have:
Work done, $W=\int_C F\cdot dr=185 \int_C dr=185(90)=16, 650 ft-lbs \approx 1.67 \times 10^{4} ft-lb$