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: arjun started a business with rs. 20,000 and is joined afterwards by anoop with rs. 30, 000. after how many months did anoop join if the profits at the end of the year are divided equally ?
Options: a. 3, b. 4, c. 5, d. 6, e. 7
[A]: b


[Q]: Problem: if the simple interest on a certain sum of money for 6 years is one – fifth of the sum, then the rate of interest per annum is
Options: a. 3.3 %, b. 7.2 %, c. 6.1 %, d. 5.0 %, e. 3.1 %
[A]: a


[Q]: Problem: tanks a and b are each in the shape of a right circular cylinder. the interior of tank a has a height of 10 meters and a circumference of 8 meters, and the interior of tank b has a height of 8 meters and a circumference of 10 meters. the capacity of tank a is what percent of the capacity of tank b ?
Options: a. 90 %, b. 50 %, c. 60 %, d. 70 %, e. 80 %
[A]:
e