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

[Q]: Problem: a 9 % stock yields 8 % . the market value of the stock is :
[A]: rs . 112.50


[Q]: Problem: two trains of equal length , running with the speeds of 60 and 90 kmph , take 50 seconds to cross each other while they are running in the same direction . what time will they take to cross each other if they are running in opposite directions ?
[A]: 6.6


[Q]: Problem: two cubes of their volumes in the ratio 64 : 125 . the ratio of their surface area is :
[A]:
4 :