WORD PROBLEM

Question

A family has two cars. The first car has a fuel efficiency of
40
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
1775
miles, for a total gas consumption of
50
gallons. How many gallons were consumed by each of the two cars that week?

Answer 1

40x+25y=1775 where x and y represent numbers of gallons of gasoline

x+y=50

x=50-y

substitute

40(50-y)+25y=1775

2000-40y+25y=1775

2000-15y=1775

2000-1775=15y

225=15y

y=225/15

y=15 gallons consumed by the 25 mpg car

x=35 gallons consumed by the 40 mpg car