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

[EX Q]: Problem: sachin is older than rahul by 7 years . if the ratio of their ages is 11 : 9 , find the age of sachin
[EX A]: 38.5

[EX Q]: Problem: the ratio between the sale price and the cost price of an article is 12 : 7 . what is the ratio between the profit and the cost price of that article ?
[EX A]: 5 : 7

[EX Q]: Problem: the average ( arithmetic mean ) of 7 , 8 , 10 and 11 equals the average of 2 , 9 , 13 , and
[EX A]:
12