Answer :
Compound interest formula:
[tex]CI=P(1+\frac{r}{n})^{nt}-P[/tex]P is the principal
r is the interest rate in decimal form
n is the number of times interest is compounded
t is the time in years
For the given situation:
P= $400
r= 0.02
n= 4 (quarterly)
t=4
[tex]\begin{gathered} CI=400(1+\frac{0.02}{4})^{4\cdot4}-400 \\ \\ CI=400(1.005)^{16}-400 \\ \\ CI=33.23 \end{gathered}[/tex]