WORD PROBLEM: 2 variable & 2 equations. Let X = miles of 1st car traveled. Let Y = miles of 2nd car traveled.
"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 40 miles per gallon of gas. During one particular week, the two cars went a combined total of 1400 miles, for a total gas consumption of 55 gallons. How many gallons were consumed by each of the two cars that week?"

Question

WORD PROBLEM: 2 variable & 2 equations.  Let X = miles of 1st car traveled.  Let Y = miles of 2nd car traveled.
"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 40 miles per gallon of gas.  During one particular week, the two cars went a combined total of 1400 miles, for a total gas consumption of 55 gallons.  How many gallons were consumed by each of the two cars that week?"

anonymous · Answer

Ok, so there is a statement about total number of miles and a statement about total number of gallons. Those will make your two equations.

anonymous · Answer

First equation I got is:  x + y = 1400

anonymous · Answer

I'm not sure what eq2 is

anonymous · Answer

Good. Note that miles ÷ miles/gallon = number of gallons.

anonymous · Answer

OK.  I'm trying to figure out Eq2 but having a hard time.  Give me another moment

anonymous · Answer

is it 20x + 40y =55 ?

anonymous · Answer

or is it x/20 + y/40 = 55

anonymous · Answer

The second one.

anonymous · Answer

Ok let me try to figure this out then

anonymous · Answer

It's a pretty easy one once you clear the fractions. You can probably do it mentally.

anonymous · Answer

x = 800 and y = 600.  I checked it in 2nd equation and got 55 gal.