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

Ex Input:
Problem: find the area of trapezium whose parallel sides are 20 cm and 18 cm long , and the distance between them is 10 cm ?

Ex Output:
190 cm 


Ex Input:
Problem: two trains running in opposite directions cross a man standing on the platform in 37 seconds and 27 seconds respectively and they cross each other in 29 seconds . the ratio of their speeds is :

Ex Output:
1 : 


Ex Input:
Problem: a survey of n people in the town of eros found that 50 % of them preferred brand a . another survey of 125 people in the town of angie found that 60 % preferred brand a . in total , 55 % of all the people surveyed together preferred brand a . what is the total number of people surveyed ?

Ex Output:

25