The amount of money paid A on a loan of P dollars at an annual interest rate of r percent, compounded n times per year for t years is:
A = P(1 = r/n)^nt
This means that if we want to take the amount we paid for the item (A), the amount the item is worth (P), the number of payments per year (n=52, since we make one payment every week), and the number of years we pay for it (t, the number of payments divided by 52), we can solve this equation for the interest rate r we are paying. We get
r = 52(a/p)^1/52t - 52
Use this formula to compute the interest rate you are being charged on each of the items.
Ashley "Loric-Smoke" 3- Piece Sectional
A= $29.99
P = $2339.22
t = 78 payments/ 52 weeks = 1.5
Signature Design by Ashley "Coralayne" 6-Piece Queen Bedroom Set
A= $39.99
P = $3639.09
t = 91 payments/ 52 weeks = 1.75
ClassicFlame "Granite" Electric Fireplace TV Stand
A= $19.99
P = $799.60
t = 40 payments/ 52 weeks = 0.77