A family has two cars. The first car has a fuel efficiency of 30 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 1800 miles, for a total gas consumption of 50 gallons. How many gallons were consumed by each of the two cars that week?
One car 40 miles /gallon other car 30 miles/gallon .. Total miles = 165 gas used = 45 gallons ... let first car drive x miles second car drive y miles .. x/40 + y/30 = 45 (30x+40y)/30*40 = 45 30x+40y = 45*40*30 30x+40y=54,000
