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

Input: Consider Input: Problem: tourist purchased a total of 30 travelers checks in $ 50 and $ 100 denominations . the total worth of the travelers checks is $ 1800 . how many checks of $ 50 denominations can he spend so that average amount ( arithmetic mean ) of the remaining travelers checks is $ 100 ?

Output: 2


Input: Consider Input: Problem: the population of a city is 415600 . it increased by 25 % in the first year and decreased by 30 % in the second year . what is the population of the city at the end of second year ?

Output: 363650


Input: Consider Input: Problem: we invested a total of $ 1,000 . we invested one part of the money at 3 % and the rest of the money at 6 % . the total investment with interest at the end of the year was $ 1 , 052.50 . how much money did we invest at 3 % ?


Output: $ 250