Question 545213
The interest rate "r" to in crease your investemnt "p" to the amount "a" in "t" years is found br "r" = index "t" (radicand a/p)-1.  What interest rate would be required to increase your investment of $2700. to $3600. over three years? 
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3600 = 2700*(1 + r)^3  (compounded annually, you didn't specify)
(1+r)^3 = 4/3
1+r =~ 1.10064
--> 10%