Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

[Q]: Problem: a man goes to shopkeeper and says that if u give me as much as i have, i will spend rs. 10 / - on ur shop. shopkeeper agrees and man moves to another shopkeeper ans asked same. at 3 rd shop after all the transaction, he was left with no money. find the initial amount with the man
Options: a. 5.75, b. 6.75, c. 7.75, d. 8.75, e. 9.75
[A]: d


[Q]: Problem: the average age of 17 persons in a office is 15 years. out of these, the average age of 5 of them is 14 years and that of the other 9 persons is 16 years. the age of the 15 th person is ?
Options: a. 39, b. 41, c. 45, d. 42, e. 50
[A]: b


[Q]: Problem: an assembly line produces 15 cogs per hour until an initial order of 60 cogs is completed. the speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. what is the overall average output, in cogs per hour, for the assembly line during this whole time ?
Options: a. 20, b. 22, c. 24, d. 26, e. 28
[A]:
c