Answer
Please see the work below.
Work Step by Step
We know that
$K_c=\frac{[product]^{coefficient }}{[reactant]^{coefficient }}$
$\implies K_c=\frac{[HI]^2}{[H_2][I_2]}$
We plug in the known values to obtain:
$K_c=\frac{(0.375)^2}{0.0747(0.0343)}=54.9$