Question 176743
Let the amount of miles that the car that consumed 30 gallons of gas went, be x
Then the amount of miles that the car that consumed 20 gallons of gas went, is 1,300 – x


Then,                            {{{(x)/(30)}}}+{{{(1300-x)/(20)}}}={{{50}}}


2x    +   3(1,300   -   x)    =    3,000

2x   +   3,900   -   3x   =   3,000
x     =     900


Since the car that consumed 30 gallons of gas went 900 miles that week, then the average gas mileage it got was 900  ÷  30   =  30 miles per gallon


Since the car that consumed 20 gallons of gas went 1,300 – 900, or 400 miles that same week, then the average gas mileage it got was 400  ÷  20   =  20 miles per gallon