For an initial amount P in a savings account with annual interest r, after t months the total interest earned is given by:
[tex]I=P\lbrack(1+r)^{\frac{t}{12}}-1\rbrack[/tex]For P = $58400, r = 0.09 and t = 3, we have:
[tex]\begin{gathered} I=58400\lbrack1.09^{\frac{1}{4}}-1\rbrack \\ I=\text{ \$1271.85} \end{gathered}[/tex]