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

Ex Input:
Problem: two cubes have their volumes are in the ratio 1 : 27 . find the ratio of their surface area ?

Ex Output:
1 : 9', 'd ) 2 : 7', 'e ) 3 : 11'


Ex Input:
Problem: the ratio between the sale price and the cost price of an article is 12 : 7 . what is the ratio between the profit and the cost price of that article ?

Ex Output:
5 : 7


Ex Input:
Problem: on a saturday night , each of the rooms at a certain motel was rented for either $ 40 or $ 60 . if 10 of the rooms that were rented for $ 60 had instead been rented for $ 40 , then the total rent the motel charged for that night would have been reduced by 40 percent . what was the total rent the motel actually charged for that night ?

Ex Output:

$ 500