You spend $20 total on tubes of paint and disposable brushes for an art project. Tubes of paint cost $4.00 each and paintbrushes cost $0.50 each. You purchase twice as many brushes as tubes of paint. How many brushes and tubes of paint do you purchase?
You are buying 2 items so let's use two different variables to represent each: p = number of tubes of paint b = number of disposable brushes cost = price per item × number of items Equations from information given: 4p + 0.50b = 20 ← from the first 2 sentences 2p = b ← if there are twice as many brushes as paint tubes you need 2 times paint tubes to equal number of brushes Solve the problem by using substitution... 1b equals 2p so replace b with that: 4p + 0.50(2p) = 20 4p + 1p = 20 ← 0.50 is half so half of 2p is 1p 5p = 20 ← combine like terms p = 4 ← divide both sides of the equation by 5 Recall the equation 2p = b replace p with 4 2(4) = b 8 = b ANSWER: You purchased 4 tubes of paint and 8 disposable brushes.
