Question

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 15 miles per gallon of gas. during one particular week, the two cars went a combined total of 725 miles, for a total gas consumption of 40 gallons. how many gallons were consumed by each of the two cars that week?

Answer 1

Car A consumes 25 gallon and car B consumes 15 gallon.

Explanation:

Given,

The fuel efficiency of car A = 20 miles per gallon.

The fuel efficiency of car B = 15 miles per gallon.

In a week, two cars went 725 miles and consumed 40 gallons.

To find the consumption of each car in that week.

Let,

Car A consumed x gallon

Car B consumed y gallon.

According to the problem,

x+y = 40 ----- (1)

20x+15y = 725

or, 4x+3y = 145 -------- (2)

From (1) we get, x = 40-y

Putting the value of x in (2) we get,

4(40-y)+3y = 145

or, 160-4y+3y = 145

or, -y = 145-160

or, y = 15

From (1) we get, x = 40-15 = 25

Hence,

Car A consumes 25 gallon and car B consumes 15 gallon.