keeping in mind that 9 months is not even a year, since there are 12 months in a year, then 9 months is just 9/12 of a year, or 3/4, thus
[tex]\bf ~~~~~~ \textit{Simple Interest Earned Amount}\\\\
A=P(1+rt)\qquad
\begin{cases}
A=\textit{accumulated amount}\\
P=\textit{original amount deposited}\to& \$1859.69\\
r=rate\to 2.4\%\to \frac{2.4}{100}\to &0.024\\
t=years\to \frac{9}{12}\to &\frac{3}{4}
\end{cases}
\\\\\\
A=1859.69\left( 1+0.024\cdot \frac{3}{4} \right)\implies A=1859.69(1.018)[/tex]
