You sell small and large candles at a craft fair small candles cost four dollars each and large candles cost six dollars each you collect $144 selling a total of 28 candles how many of each size candles did you sell

Let x = the number of small candles sold

Let y = the number of large candles sold

You are given two pieces of information:

(1) Number of candles sold: x + y = 28

(2) Revenue based on cost per candles sold: 4x + 6y = 144

Two equations, two unknowns - Solving by substitution (x = 28 - y)

4 * (28-y) + 6y = 144

112 - 4y + 6y = 144

112 + 2y = 144

2y = 32

y = 16

If y = 16, back substitute to find x = 12