Answer:
136 miles
Step-by-step explanation:
Write an equation to represent the cost of the rental, and then solve the equation to find the number of miles.
Let x = number of miles.
The total cost is the cost per mile plus the base fee.
1 mile costs $0.90
2 miles cost $0.90 * 2
x miles cost $0.90 * x, or simply 0.9x
The base fee is $16.95, so the total to rent for x miles is 0.9x + 16.95
The equation
c = 0.9x + 16.95
gives you the cost, c, for a rental of x miles.
We are told the total cost was $139.35. Replace c with 139.35, and solve for x, the number of miles.
139.35 = 0.9x + 16.95
Switch sides.
0.9x + 16.95 = 139.35
Subtract 16.95 from both sides.
0.9x = 122.4
Divide both sides by 0.9
x = 122.4/0.9
x = 136
Answer: 136 miles