SOLUTION: If you save 10$ one month, 12$ the next month, 14$ the next month, and so on, how long will you take to save a total of 400$? How would you make this into a formula?

Question 346655: If you save 10$ one month, 12$ the next month, 14$ the next month, and so on, how long will you take to save a total of 400$?
How would you make this into a formula?
Answer by jrfrunner(365) (Show Source): You can put this solution on YOUR website!
you are looking for summing an arithmetic series
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the sequence is 10,12,14,..... such that is sum =400
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where is the difference between to consecutive sequence numbers, in this case and
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=
from 1 to n == ===
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since we want to know when this sum=400
-->
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solve for n using quadratic formula

n=-25 or n=16, since we want the number of months, we take the positive answer
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