Problema Solution
A family has two cars. The first car has a fuel efficiency of 15 miles per gallon of gas and the second has a fuel efficiency of 20 miles per gallon of gas. During one particular week, the two cars went a combined total of 1000 miles, for a total gas consumption of 60 gallons. How many gallons were consumed by each of the two cars that week?
Answer provided by our tutors
let 'x' represent the number of miles driven at 15mpg, then '1000-x' represents the number of miles driven at 20mpg
let 'g' represent the number of gallons consumed at 15mpg, then '60-g' represents the number of gallons consumed at 20mpg
gallons = miles/mpg
we have these equations:
g = x/15
60-g = (1000-x)/20
solving this system we obtain:
g=40
x=600
60-40=20
the 15mpg car consumed 40 gallons, the 20mpg car consumed 20 gallons