SOLUTION: Starting with a sum of 4,638.40 I must find a way to subtract 25% from the sum a total of 162 times until I deplete the sum and enter negative numbers. I'm putting this into an Ex

Click here to see ALL problems on Sequences-and-series

Question 1019618: Starting with a sum of 4,638.40 I must find a way to subtract 25% from the sum a total of 162 times until I deplete the sum and enter negative numbers. I'm putting this into an Excel spreadsheet. It's been decades since I've been in math class. Which algebraic formula would I use? Thank you.
Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website!
A1=4638.40
A2=(0.75*A1), which is 25% less than 4638.40
A3=(0.75*A2), etc.
There are more elegant ways to do this, but it will work, EXCEPT it never become negative. It will become 0 to some number of decimal places, and you can't subtract 25% of 0 and get a negative difference. Perhaps if this were 2,5%, it would be close to zero ($76.75) after 162 iterations.
------------------------