SOLUTION: When Mary's car's tire pressure is 30 pounds per square inch (psi), it averages 20.8 mpg of gasoline. If the tire pressure is increased to 35 psi, the car averages 21.6 mpg of gas

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: When Mary's car's tire pressure is 30 pounds per square inch (psi), it averages 20.8 mpg of gasoline. If the tire pressure is increased to 35 psi, the car averages 21.6 mpg of gas      Log On


   

Question 273787: When Mary's car's tire pressure is 30 pounds per square inch (psi), it averages 20.8 mpg of gasoline. If the tire pressure is increased to 35 psi, the car averages 21.6 mpg of gasoline. If Mary drives an average of 20,000 miles per year, how many gallons of gasoline will she save in one year by increasing her tire pressure from 30 psi to 35 psi (round to the nearest unit)? Show your step by step work!

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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When Mary's car's tire pressure is 30 pounds per square inch (psi), it averages 20.8 mpg of gasoline.
If the tire pressure is increased to 35 psi, the car averages 21.6 mpg of gasoline.
If Mary drives an average of 20,000 miles per year, how many gallons of gasoline
will she save in one year by increasing her tire pressure from 30 psi to 35 psi
(round to the nearest unit)? Show your step by step work!
:
Find number of gallon consumed at each pressure
30 psi: 20000%2F20.8 = 961.5 gal
35 psi: 20000%2F21.6 = 925.9 gal
-------------------------------- subtract
gallons saved = 35.6 ~ 36 gal