Solving an Application Involving Mixtures

Question

Ethanol fuel mixtures have "E" numbers that indicate the percentage of ethanol in the mixture by volume. For example, E10 is a mixture of 10% ethanol and 90% gasoline. How much E2 should be mixed with 4500 gal of E10 to make an E8 mixture?

Answer 1

As per the problem definition, 4500 gal of E10 contains 450 gal of ethanol. Assuming the volume X of E2 has been added, the following equation leads to the solution:

 

(0.02X + 450) / (X + 4500) = 0.08

 

Simplify:

 

0.02X + 450 = 0.08X + 4500 * 0. 08

 

0.06X = 450 -360

 

X= 1500

 

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