Question 892744
plan 1 costs 10 dollars a day plus 10 cents a mile.


the formula for plan 1 is c = .10 * 300 + 10 = 40 dollars.


plan 2 costs 0 dollars a day plus 14 cents a mile.


the formula for plan 2 is c = .14 * 300 = 42 dollars.


plan 1 is cheaper because the total cost for plan 1 is 40 dollars while the total cost for plan 2 is 42 dollars.


the formula c = rx + b works but you have to be careful what gets assigned to what.


for plan 1, r = .10 and x = 300 and b = 10
for plan 2, r = .14 and x = 300 and b = 0


note that if you had rented for more than a day, the formula would have had to have been c = rx + by
r would be the cost per mile.
x would be the number of miles.
b would be the cost per day.
y would be the number of days.