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

Ex Input:
Problem: the ratio between b and y is 7 / 9 ; b and y are increased by 4 , what is the ratio between the new values of b and y ?

Ex Output:
it can not be determine


Ex Input:
Problem: a diagonal of a polygon is an segment between two non - adjacent vertices of the polygon . how many diagonals does a regular 20 - sided polygon have ?

Ex Output:
170', 'c ) 1425', 'd ) 2025', 'e ) 2500'


Ex Input:
Problem: seller selling an apple for rs . 18 , a seller loses 1 / 6 th of what it costs him . the cp of the apple is ?

Ex Output:

19