Original price of the swimsuit = x
If something was discounted 65%, that means you are paying 35% for it.
(100% - 65% = 35% or 0.35)
x(0.35) = 20.30
divide both sides by 0.35
x = 58
The swimsuit was originally 58 dollars.
Number of compounding periods is
n=12months×3years=36
I assume that
The total interest=
monthly payment×number of compounding periods - the amount of the present value of an annuity ordinary
I=x×n-pv
Let monthly payment be X
I =Total interest is 1505.82
The present value of an annuity ordinary is
Pv=X [(1-(1+0.09/12)^(-36))÷(0.09/12)]
now plug those in the formula of the total interest above
I=x×n-pv
1505.72=36X-X [(1-(1+0.09/12)^(-36))÷(0.09/12)]
Solve for X using Google calculator to get the monthly payment which is
X=330.72
Check your answer using the interest formula
36×330.72−330.72×((1−(1+0.09
÷12)^(−12×3))÷(0.09÷12))
=1,505.83
