12 small candles, 16 large candles.
HOW TO SOLVE
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
Double check using revenue generated:
4x + 6y = 144
4(12) + 6(16) =? 144
48 + 96 = 144
