看看这道SAT的题，怎么解。。

The total cost of a car rental is the sum of
1. a basic fixed rental charge for the car, and
2. An additional charge for every 25 miles traveled.

If the total cost to rent a car and drive it 50 miles is $200 and the total cost to rent a car and drive it 200 miles is $245, what is the total cost , in dollars to rent a car and travel 450 miles?