Question

A lotion is made from an oil blend costing $1.50 per ounce and glycerin costing $1.00 per ounce. Four ounces of lotion costs $5.50.

Answer 1

X-ounces of an oil blend,
y - ounces of glycerin
x + y = 4    ⇒   y = 4 - x
1.5 x + y = 5.50
1.5 x + 4 - x = 5.50
0.5 x = 5.50 - 4
0.5 x = 1.50
x = 3
y = 4 - 3 = 1
There are 3 ounces of an oil blend and 1 ounce of glycerin.