Question

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 30 miles per gallon of gas. During one particular week, the two cars went a combined total of 975 miles, for a total gas consumption of 45 gallons. How many gallons were consumed by each of the two cars that week?

Answer 1

Answer: We can start by using algebra to represent the information given in the problem. Let x be the number of gallons consumed by the first car and y be the number of gallons consumed by the second car.

We know that:

x + y = 45 (the total number of gallons consumed by both cars)

15x + 30y = 975 (the total number of miles driven by both cars, given the fuel efficiency of each car)

We have two equations and two unknowns, so we can use these equations to solve for the value of x and y.

From the first equation, we can solve for x:

x = 45 - y

We can substitute this expression of x into the second equation:

15(45 - y) + 30y = 975

Simplifying the left side of the equation:

675 - 15y + 30y = 975

Subtracting 675 from both sides:

15y = 300

And finally divide both sides by 15:

y = 20

So the second car consumed 20 gallons of gas that week.

We can substitute this value of y back into the equation x = 45 - y to find the value of x

x = 45 - 20 = 25

So the first car consumed 25 gallons of gas that week.

Explanation: