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

Ex Input:
Problem: the sum of all the digits of the integers from 18 to 21 inclusive is 24 ( 1 + 8 + 1 + 9 + 2 + 0 + 2 + 1 = 24 ) . what is the sum t of all the digits of the integers from 0 to 99 inclusive ?

Ex Output:
900


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: a man buy a book in rs 50 & sale it rs 70 . what is the rate of profit ? ? ?

Ex Output:

40 %