A family has two cars. The first car has a fuel efficiency of 20 miles per gallon of gas and the second has a fuel efficiency of 25 miles per gallon of gas. During one particular week, the two cars went a combined total of 1200 miles, for a total gas consumption of 55 gallons. How many gallons were consumed by each of the two cars that week?

Question

anonymous · Answer

let x=gas consumed by 1st car
40-x =gas consumed by 2nd car
distance traveled=fuel efficiency*gas consumed
..
20x+25(40-x)=925
20x+1000-25x=925
5x=75
x=15
40-x=25
gas consumed by 1st car=15 gal
gas consumed by 2nd car=25 gal

anonymous · Answer

gallons were consumed by each of the two cars that week are 40 and 15

Solution:Set the miles of the first car is X,  the gallons consumed is Y

              then (55-Y)x 20 =1300- X

                      Y x 25 = X

             so Y = 40,   X = 1000