TASK DEFINITION: The task is to generate the correct answer for a given math problem.
PROBLEM: Problem: a shopkeeper loses 15 % , if an article is sold for rs . 102 . what should be the selling price of the article to gain 20 % ?

SOLUTION: rs . 144

PROBLEM: Problem: a group of men decided to do a work in 55 days , but 15 of them became absent . if the rest of the group did the work in 60 days , find the original number of men ?

SOLUTION: 180

PROBLEM: Problem: two trains of length 100 meters and 200 meters are 450 meters apart . they are moving towards each other on parallel tracks , at speeds of 90 km / h and 72 km / h . after how many seconds will the trains meet ?

SOLUTION:
10