Question 1174670

A certain car ideally requires an engine oil which is composed of 91.50% base oil and the rest in additives. How many gallons of 87.00% engine oil and how many gallons of 93.50% engine oil must be combined to produce 50.00 gallons of 91.50% engine oil? rounded up 2 decimals.
<pre>Let amount of 87% oil be E
Then amount of 93.5% oil = 50 - E
We then get: .87E + .935(50 - E) = .915(50)			
.87E + .935(50) - .935E = .915(50)
.87E - .935E = .915(50) - .935(50)			
- .065E = - .02(50)			
Amount of 87% oil, or {{{highlight_green(matrix(1,8, E, "=", (-.02(50))/(- .065), "=", "15.38461538,", or, 15.38, gallons))}}}
It should be easy for you to find the amount of 93.5% oil!