Question

The first car has a fuel efficiency of 15 miles per gallon of gas and the second has a fuel efficiency of 40 miles per gallon of gas. during one particular week, the two cars went a combined total of 1450 miles, for a total gas consumption of 55 gallons. how many gallons were consumed by each of the two cars that week?

Answer 1

1st car = x

2nd car = y

x +y = 55 gallons rewrite as x=55-y

15x + 40y = 1450 miles

15(55-y)+40y=1450

825-15y + 40y=1450

825+25y=1450

25y=625

y = 25

x = 55-25=30

1st car used 30 gallons and 2nd car used 25 gallons