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;
1.5 · x + 1 · y = 5.50
x + y = 4
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1.5 x + y = 5.5
x + y = 4 / · ( -1 )
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1.5 x + y = 5.5
+
- x - y = - 4
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0.5 x = 1.5
x = 1.5 : 0.5
x = 3
3 + y = 4
y = 1
There are 3 ounces of an oil blend and 1 ounce of glycerin in 4 ounces of lotion.