Question

Alex is painting a house. He uses 1/3 of the paint he bought on the dining room. He uses twice as much on the living room as on the kitchen, where he uses 1 1/2 gallons. He has 1 1/2 gallons of paint left. How much paint did Alex buy?

Answer 1

bought x gallons
dining room = (x/3) gallons
kitchen = 1.5 gallons
living rm = 3 gallons
leftover = 1.5 gallons
so
(x/3) + 6 = x

6 = 2 x/3

x = 9 gallons