Mike started a savings account by depositing $9. Each month he deposits more money than the month before. At the end of 41 months, he has saved $9,204.50. How much more does he deposit each month?
A. $11.00
B. $11.50
C. $12.00
D. $12.50

Question

Mike started a savings account by depositing $9. Each month he deposits more money than the month before. At the end of 41 months, he has saved $9,204.50. How much more does he deposit each month?
A. $11.00
B. $11.50
C. $12.00
D. $12.50

campbell_st · Answer

well don't you have an arithmetic sequence. If $x is added every month you have 

  9 + (9 +x) + (9 +2x) + (9 + 3x) +....

and you know the sum is $9204.50

anonymous · Answer

Yes and I have worked it out but I must be doing something wrong. When I work with the choices given I end up getting a sum less than $9,205.50

campbell_st · Answer

same here I got the additional amount be $10.775

anonymous · Answer

And it doesn't say to round or anything like that... It's a strange question :/

anonymous · Answer

@hartnn

campbell_st · Answer

well its interesting in that $11 puts you over the  total saving amount...