The equation for the rental charge includes the following; a fixed rental fee, a charge for gas and charge for miles covered. If the fixed charge for rental is a, the charge for gas is b and the charge per mile is d, then the total rental charge would be;
Cost = a + b + d
For Rapid rental, this becomes
Cost = 40 + 15 + 0.25d
Cost = 55 + 0.25d
However for Capital cars, to rent the same car would cost;
Cost = 45 + 0.35d ( note that Capital charges 45 for rental and gas, so a + b = 45)
The cost per miles for the same car can be expressed as an equation of both expressions. That is;
Having calculated the value of d, we can now substitute this into the cost function to get the cost for each rental.
For Rapid Rental, the cost is;
For Capital Cars, the cost is;
Hence the cost in both rental services is $80