Question 1025671
A petroleum company has two different sources of crude oil. The first source provides crude oil that is 50% hydrocarbons, and the second one provides crude oil that is 75% hydrocarbons. In order to obtain 60 gallons of crude oil that is 70% hydrocarbons, how many gallons of crude oil must be used from each of the two sources? 
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Quantity:: f + s = 60 gallons
Hydro Eq:: 0.50f + 0.75s = 0.70*60
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50f + 50s = 50*60
50f + 75s = 70*60
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Subtract and solve for "s"::
25s = 20*60
s = (4/5)60
s = 48 gallons (amt. of 75% needed)
f = 12 gallons (amt. of 50% needed)
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Cheers,
Stan H.
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