To calculate the total miles he is allowed we must setup an expression for total cost of the car per day. Cost = 43.09 + .04x where x is the number of miles driven. To find out the number of miles driven with $100, we plug in $100 for cost and solve for x. Doing this we get 100 = 43.09 + .04x, where .04x = 56.91 and solving for x we get x=1422.75 or 1422 miles. In this case we do not round up since adding an additional mile would put us over the $100 budget. Answer = 1422 miles.
