The simple interest formula is given by
[tex]I=p\cdot r\cdot t[/tex]
where I is the interest, p is the principal, r is the interest rate and t the time in years.
In our case,
[tex]\begin{gathered} P=2975 \\ r=0.065 \\ t=3\frac{1}{2} \end{gathered}[/tex]
However, in order to use the above formula, we must convert the time into a simple fraction form, that is
[tex]3\frac{1}{2}=\frac{2\cdot3+1}{2}=\frac{7}{2}[/tex]
Then, by subsituting our values into the simple interest formula, we get
[tex]I=(2975)(0.065)(\frac{7}{2})[/tex]
which gives
[tex]\begin{gathered} I=\frac{13563.625}{2} \\ I=676.8125 \end{gathered}[/tex]
Then,by rounding to the nearest cent, the interest is $676.81
