Question

A family has two cars. The first car has a fuel efficuency of 15 miles per gallon of gas and the second has a fuel efficiency of 35 miles per gallon of gas. During one particular week, the two cars went a combined total of 1925 miles, for a total gas consumtion of 75 gallons. How many gallons were consumed by each of the two cars that week?​

Answer 1

Answer:

x= 35 gallons consumed by 1st car

and y= 40  gallons consumed by 2nd car

Step-by-step explanation:

Fuel efficiency of 1st car = 15 miles per gallon

Fuel efficiency of 2nd car = 35 miles per gallon

Let x= gallons consumed by 1st car

and y= gallons consumed by 2nd car

Total gallons consumed by both cars = 75

so, we can write

x + y = 75

Miles covered by both cars = 1925 miles

and we know, Fuel efficiency of 1st car = 15 miles per gallon

Fuel efficiency of 2nd car = 35 miles per gallon

we can write the equation as

15 x + 35 y = 1925

where x and y are gallons consumed by 1st and 2nd car.

We have two equation now,

x + y = 75                   (1)

15 x + 35 y = 1925     (2)

Multiplying eq(1) with 15 and subtracting eq (1) and 2

15 x + 15 y = 1125

15 x + 35 y = 1925

-       -            -

_______________

0 - 20 y = -800

y= -800 / -20

y = 40

Putting value of y in equation 1

x + y = 75

x + 40 = 75

x= 75 - 40

x = 35

x= 35 gallons consumed by 1st car

and y= 40  gallons consumed by 2nd car