Answer: 1000 gallons
Step-by-step explanation:
This situation can be modelled by the following equation:
[tex]7\% x + 4\% (2000 gallons)=5\%(x+2000 gallons)[/tex]
Since [tex]7\%=\frac{7}{100}=0.07[/tex], [tex]4\%=\frac{4}{100}=0.04[/tex] and [tex]5\%=\frac{5}{100}=0.05[/tex], we can rewrite the equation as follows:
[tex]0.07 x + 0.04 (2000 gallons)=0.05(x+2000 gallons)[/tex]
Then we have to find [tex]x[/tex]:
[tex]0.07 x + 80 gallons=0.05x+100 gallons[/tex]
[tex]x=1000 gallons[/tex]
Hence, 1000 gallons of gasoline that is 7% ethanol must be added.
