$5\mathrm{.}1.$ A work center consists of three machines each working a $16-$hour day for five days a week. What is the weekly available time?

Answer. $240$ hours per week

$5\mathrm{.}2.$ The work center in problem $5\mathrm{.}1$ is utilized $80\%$ of the time. What are the hours per week actually worked?