Problem $2(10$ points$)$ A trucking company is exploring the cost$-$to$-$cost trade$-$offs given the following information:

Fuel cost $($diesel$)$: $$3\mathrm{.}5$ per gallon

Mileage at $70mph$:$5$ miles per gallon

Cost of delay if delivery commitment is missed: $$75.$

What speed should the trucks use?

Distance to be traveled: $700$ miles Mileage at $60mph$ : $6$ miles per gallon