A crawler hoe having a $\frac{21}{4}-$cy bucket and whose cost per hour, including the wages to

an operator, is $$67,$ will excavate and load haul units under each of the stated conditions.

The maximum digging depth of the machine is $20$ ft $.$ Determine the cost per bank cubic

yard for each condition. $($Condition $1\mathrm{.}300bc\frac{y}{h}r,$$$\frac{0\mathrm{.}223}{b}cy$; Condition $2\mathrm{.}319bc\frac{y}{h}r,$

$$\frac{0\mathrm{.}210}{b}cy$; Condition $3\mathrm{.}128bc\frac{y}{h}r,$$$\frac{0\mathrm{.}523}{b}cy)$