SOLUTION: If Kachina Caron invested $1200 in a simple interest account and earned $27 in 3 months, what is the annual interest rate?

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Question 1146682: If Kachina Caron invested $1200 in a simple interest account and earned $27 in 3 months, what is the annual interest rate?
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


(1) Find what percent of the $1200 investment the $27 of interest is:

27%2F1200+=+0.0225 = 2.25%

(2) 3 months is 1/4 year. Determine the annual interest if the interest in 1/4 year is 2.25%:

0.225%2A4+=+0.09 = 9%

Or, formally....

interest = principal times rate times time

I+=+prt
27+=+%281200%29%28x%29%281%2F4%29
27+=+300x
x+=+27%2F300+=+.09 = 9%