Need help solving word problem

Question

2 cars 1st car get 35 miles per gallon and the 2nd car gets 15 miles per gallon together they use 49 gallons of gas and went 900 miles. How many gallons of gas did each car us

Answer 1

x+y = 49

35x + 15y = 900

35x + 15(49-x) = 900

35x + 735 - 15x = 900

20x = 165

x = 165/20 = 8.25

y = 49 -8.25 = .40.75