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

[Q]: Problem: by selling an article for $ 195 , a person gains $ 45 . what is the gain % ?
[A]: 30 %


[Q]: Problem: how many liters of a 40 % iodine solution need to be mixed with 35 liters of a 20 % iodine solution to create a 34 % iodine solution ?
[A]: 13


[Q]: Problem: the average age of 15 students of a class is 15 years . out of these , the average age of 8 students is 14 years and that of the other 6 students is 16 years , the age of the 15 th student is
[A]:
17