Diana invested $3000 in a savings account for 3 years. she earned $450 in interest over that time period. what interest rate did she earn? use the formula i=prt to find your answer, where i is interest, p is principal, r is rate and t is time. enter your solution in decimal form rounded to the nearest hundredth. for example, if your solution is 12%, you would enter 0.12.

Actually the formula should be "r" to the power of "t"
Interest = Principal * Rate^time
We have to solve for the rate and the equation to use is:

log(1 + rate) = {log(total) -log(Principal)} ÷ Years

log(1 + rate) =[ log (3450) - log (3000) ] / 3

log(1 + rate) = (3.5378190951 - 3.4771212547) / 3

log(1 + rate) = 0.0606978404 / 3

log(1 + rate) = 0.0202326135

10^ 0.0202326135 = 1.0476895532

(1 + rate) = 1.0476895532

rate = .0476895532

SOURCE:
http://www.1728.org/compint2.htm