Math
posted by Betsy .
What is the principle and the interest?
A=$2719.50 P= ? r=6.1% t=20 years
What is the interest rate?
Balance= $3742.50 p=$3000 interest rate= ? t=45 months

Assuming simple Interest:
I = Po*r*t = 2719.50*0.061*20 = $3317.79
P = Po + I = 2719.50 + 3317.79=$6037.29.
P = Po + Po*r*t = $3742.50.
3000 + 3000*r*3.75 = 3742.50
3000 + 11250r = 3742.50
11250r = 3742.503000 = 742.50
r = 0.066 = 6.6%/yr.