Question

Ms. Finely uses 10.5 gallons of gasoline to drive the first 598 miles of the trip. How many gallons of gasoline would she need to drive 750 miles?

Answer 1

Write and solve an equation of ratios:

10.5 gal         x
----------- = ----------- resutls in 598x = 7875.  Solving for x, x = 13.17 gallons 
 598 mi      750 mi                                          (ans)

Answer 2

Assuming we use gallons per mile as our starting point, 10.5 gallons gets her 598 miles.

We can solve this by setting up am equation:
10.5gallons / 598 = xgallons / 750

Multiply by the 750 miles:
750 * 10.5 / 598 = 13.169gallons