Question 911762: Marsha and Kan both invested money on March 1, 2007. Marsha invested $9,000 at Bank A where the interest was compounded quarterly. Jan invested $6,000 at Bank B where the interest was compounded continuously. On March 1, 2012, Marsha had a balance of $11,789.68 while Jan had a balance of $7,504.50. What was the interest at each bank?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Marsha and Kan both invested money on March 1, 2007.
Marsha invested $9,000 at Bank A where the interest was compounded quarterly.
Jan invested $6,000 at Bank B where the interest was compounded continuously.
On March 1, 2012, Marsha had a balance of $11,789.68 while Jan had a balance of $7,504.50.
What was the interest at each bank?
:
From the information given, we know both had money invested for 5 yrs
:
M
 = 11789.68
 = 
use logs here
 = 
= .1172595
 = 
 = .005862975
find the antilog
1 +  = 1.0136
= 1.0136 - 1
= .0136
mult both sides fy 4
r = .054366 ~ 5.44% interest
:
J
 = 7504.50
 = 
use natural logs here, ln of e = 1, so we have a simple equation
5r = 
5r = .21046
r = 
r = .04475 ~ 4.475% interest
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