Question 986434
Yesterday you borrowed $20 from your brother. Every day that you don't pay back, you owe $.50 more. So today, day one, you owe him $20.50, on day two you will owe him $21.00, on day three you will owe him $21.50, etc. if you still haven't paid him back his much will you owe him on day 25?
<pre>Let amount owed after d days be A(d)
Then we get the equation: A(d) = 20 + d(.5)
With d, or number of days being 25, we get: A(25) = 20 + 25(.5)
A(25) = 20 + 12.5
A(25), or amount owed on day 25 = {{{highlight_green("$"32.50)}}}