Data:
P (Principal) = $2500
I (Simple Interest) = $840
t (time) = 6 years
r (percentage rate) = ?
Formula:
\(I = P*r*t\)
Solving:
\(I = P*r*t\)
\(840 = 2500*r*6\)
\(840 = 15000r\)
\(15000r = 840\)
\(r = \frac{840}{15000}\)
\(r = 0.056\to\:\boxed{\boxed{r =5.6\%}}\end{array}}\qquad\quad\checkmark\)