Mary is looking at the partial information left behind by her former supervisor, Lyle. She knows he used the high$-$low method to

estimate the cost function because she sees his cryptic $"$H$-$L$"$ scribbled on the page. She sees that the high point related to $31$

units at a total cost of $$250\mathrm{.}50.$ She also finds the total fixed cost estimate of $$80.$ She can't find the low point written anywhere,

and she needs the variable cost in order to estimate next month's costs.

Help Mary determine the variable cost per unit and then predict next month's costs if $29$ units are made. $($Round answers to $2$

decimal places, e$.$g$.15\mathrm{.}25.)$

Variable cost per unit

$

Next month's costs

$