The task is to generate the correct answer for a given math problem.
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Question: Problem: calculate the sum of first 60 natural numbers .

Answer: 1830


Question: Problem: joan took out a mortgage from hel local bank . each monthly mortgage payment she makes must be triple the amount of the previous month ' s payment . if her first payment is $ 100 , and the total amount she must pay back is $ 914800 , how many months will it take joan to pay back her mortgage ?

Answer: 9


Question: Problem: the average salary of 20 people in the shipping department at a certain firm is $ 1000 . the salary of 10 of the employees is $ 600 each and the salary of 6 of the employees is $ 200 each . what is the average salary of the remaining employees ?

Answer:
$ 3200