A concrete mix is designed as $1$:$1\mathrm{.}9$:$2\mathrm{.}8($by weight $),$ the $\frac{w}{c}$ ratio is $7\mathrm{.}0$ gal per sack.

$($a$)$ What is the concrete yield in cubic feet? $($b$)$ How much sand, coarse aggregate, and

Water is needed to make $45$ cubic yards?