The task is to generate the correct answer for a given math problem.

[Q]: Problem: a student chose a number , multiplied it by 2 , then subtracted 138 from the result and got 102 . what was the number he chose ?
[A]: 120


[Q]: Problem: a solution contains 8 parts of water for every 7 parts of lemonade syrup . how many parts of the solution should be removed and replaced with water so that the solution will now contain 25 % lemonade syrup ?
[A]: 2.14


[Q]: Problem: a car traveled 560 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city . if the car traveled 6 fewer miles per gallon in the city than on the highway , how many miles per gallon did the car travel in the city ?
[A]:
9