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.