Answer
$1.67$
Work Step by Step
We know that
$Q_{monoatomic}=\frac{3}{2}nRT$
and $Q_{diatomic}=\frac{5}{2}nRT$
Now $\frac{Q_{diatomic}}{Q_{monoatomic}}=\frac{\frac{5}{2}nRT}{\frac{3}{2}nRT}$
$\implies \frac{Q_{diatomic}}{Q_{monoatomic}}=\frac{5}{3}=1.67$