Answer:
EQUATION: c = 2.50m + 3
Explanation:
you know the equation is C = 2.50m + 3 because if you look at the sentence and pick it apart to better understand it you'll see in the first sentence that 3 PLUS 2.50 PER MILE. your key words are of course plus and per mile. So, in conclusion you say for every mile you have to pay 2.50 but they don't give you the number for how many miles you'd drive so automatically it's your missing value.