Problem $3$: $20$ points

A three$-$story hotel has interior columns that are spaced $20$ ft apart in two perpendicular directions.

If the loading on the flat roof is estimated to be $30l\frac{b}{f}t2,$ determine the live load supported by a

typical interior column at

$($a$)$ the ground$-$floor level, and

$($b$)$ the second$-$floor level

Hint: Read Section $1\mathrm{.}3$ about reduced live loads and review Example $1\mathrm{.}2$ in your version of the

textbook.