I don't even know if this is an nth partial sum of a geometric sequence problem but...
if someone wanted to save money to buy a used car and they saved $100 on the first day, then $75 on the second day, then $56.25 on the third day, how much will they have saved on the seventh day?
In 20 days, will they have enough to afford a used car that costs $500?
what would be the total amount they saved in that time?
thanks