Question

Suppose a fuel mixture is 5% ethanol and 95% gasoline. How much ethanol (in gallons) must you add to one gallon of the fuel so that the new fuel mixture is 10% ethanol?

Answer 1

`5/90(.056(3dp))` gallon of ethanol is added to make the mixture `10%` ethanol.

Explanation:

In one gallon fuel mixture gasoline is `0.95` gallon
In one gallon fuel mixture ethanol is `0.05` gallon
let x gallon of ethanol is added to make the mixture `10%` ethanol
`:. (x+.05) = 10/100(1+x) or 100x+5=10+10x or 90x = 5 or x=5/90` gallon of ethanol.[Ans]