Answer
$10\text{ percent}$
Work Step by Step
Substituting the known values in the given formula, $A=P(1+r)^t$, then,
\begin{array}{l}\require{cancel}
2,420=2000(1+r)^2\\\\
\dfrac{2,420}{2000}=(1+r)^2\\\\
\dfrac{121}{100}=(1+r)^2\\\\
\sqrt{\dfrac{121}{100}}=1+r\\\\
\dfrac{11}{10}-1=r\\\\
r=\dfrac{1}{10}
.\end{array}
Hence, the rate of interest is $
10\text{ percent}
.$
