The key point here is that ozone is absorbed by turpentine and oxygen is not.
So, we have 10 ml of ozone and 90 ml of oxygen in 100 ml mixture.
Since, at constant P, T the volume is proportional to moles, the ratio of moles of ozone and oxygen would be 1:9.
Let, molecular weight of ozone by x,
\(\frac{x\times 1+32\times 9}{1+9}=1.5\times 22.4\).