SOLUTION: Sam�s annual interest from an investment is $225. If Sam had invested $600 more at an annual interest rate that was 1% less, the annual interest would have been $234. What are th

Question 741167: Sam�s annual interest from an investment is $225. If Sam had invested $600 more at an annual interest rate that was 1% less, the annual interest would have been $234. What are the amount and the rate of his actual investment?
I have tried a few different things. I'm completely frustrated. This is my first time trying a tutor site, Thanks in advance for any help that you can give me! I know it involves a table, and I know the simple interest formula of I=Prt of course.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = the actual interest rate
= the lower rate

year
--------------
given:
(1)
and
(2)
-------------------------------
(2)
(2)
(2)
(2)
----------------------------------
(1)
Substitute this back into (2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
Use the quadratic formula

The rate of the investment was 7.5%
and, since
(1)
(1)
(1)
The amount of the investment was $3,000
check:
(2)
(2)
(2)
(2)
OK

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