Answer
$\approx 1.67 \times 10^{4} ft-lb$
Work Step by Step
The magnitude of gravitational force acting on the man $+$ Can of paint $=160+25=185lbs$
When we are moving in the upward direction, then we have
$F \cdot dr=185 dr$
$W=\int_C F\cdot dr=185 \int_C dr$
Here, $C$ shows a vertical line segment joining the lower and upper
part of the silo, then we have
$W=\int_C F\cdot dr=185 \int_C dr=185(90)$
or, $W=16, 650 ft-lbs \approx 1.67 \times 10^{4} ft-lb$
