One gallon of fuel mixture contains antifreeze in the ratio of 5 parts fuel to one part antifreeze. To this is added half a gallon of mixture which is one third antifreeze and two thirds fuel. What is the ratio of fuel to antifreeze in the final mixture? (Grid your answer as a fraction: fuel/antifreeze)
Correct Answer: 7/2
Explanation:
The antifreeze in the initial fuel mixture is 1/6 of one gallon.
The added mixture contains 1/3 of half a gallon = 1/6 of a gallon
The final mixture contains 1/6 + 1/6 in 1.5 gallon
2/6 antifreeze in total 9/6 gallons
Fuel in the mixture is 9/6 - 2/6 = 7/6
Ratio fuel to antifreeze = 7/6 : 2/6 = 7 : 2
Grid in as 7/2