$($a$)$

What is the average useful power output $($in W$)$ of a person who does $5\mathrm{.}00106$ J of useful work in $8\mathrm{.}40$ h$?$

$($No Response$)$ W

$($b$)$

Working at this rate, how long $($in s$)$ will it take this person to lift $1700$ kg of bricks $1\mathrm{.}60$ m to a platform? $($Work done to lift his body can be omitted because it is not considered useful output here.$)$

$($No Response$)$ s