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

[EX Q]: Problem: solve the equation for x : 6 x - 47 + 3 x = 4 + 9 - x
[EX A]: 

[EX Q]: Problem: in a garment industry , 12 men working 9 hours per day complete a piece of work in 10 days . to complete the same work in 12 days , working 15 hours a day , the number of men required is :
[EX A]: 7

[EX Q]: Problem: a certain library assesses fines for overdue books as follows . on the first day that a book is overdue , the total fine is $ 0.09 . for each additional day that the book is overdue , the total fine is either increased by $ 0.30 or doubled , whichever results in the lesser amount . what is the total for a book on the fourth day it is overdue ?
[EX A]:
$ 0.66