Quandaries
and Queries 

Hello, my name is Kat and I am not a student at this time. If I have three debts and 49% percent of total debt is loaned at 9% intrest, 34% of the debt is at 21% intrest and 17% of the total debt is at 14% intrest, how do I calculate the average rate of intrest on total debt? I just can seem to figure this one out. I need average percent of intrest rates for a program I am using to map out a pay down plan. thank you so much for any reply. (and yes I know I should pay down high intrest first! :) ) 

Hi Kat, Suppose that your total debt was $100 and calculate how much interest you would owe in one year.
Thus on $100 you owe an interest of $13.93 and hence the interest rate is
Suppose now that you total debt was $K rather than $100. What changes? The debts are
Thus I get
Thus on $K you owe an interest of $0.1393 K and hence the interest rate is
Penny 

