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.

[EX Q]: Problem: two pipes a and b can fill a tank in 36 hours and 46 hours respectively. if both the pipes are opened simultaneously, how much time will be taken to fill the tank ?
Options: a. 20.195 hrs, b. 21.195 hrs, c. 22.195 hrs, d. 23.195 hrs, e. 20.495 hrs
[EX A]: a

[EX Q]: Problem: a shopkeeper sold 30 articles at the cost price of 35 articles. then find the profit % or lost %
Options: a. 12 %, b. 15 %, c. 16.67 %, d. 18 %, e. 22 %
[EX A]: c

[EX Q]: Problem: the length of rectangle is thrice its breadth and its perimeter is 104 m, find the area of the rectangle ?
Options: a. 507 sq m, b. 356 sq m, c. 452 sq m, d. 428 sq m, e. 525 sq m
[EX A]:
a