Graham's Law of Effusion:
The rate of effusion of a gas is inversely proportional to the molar mass of the gas.
rate of gas 1 / rate of gas 2 = sqrt MW gas 2 / sqrt MW gas 1
Since we are only being asked to COMPARE the rates of CO2 and O3, we can just choose an arbitrary rate for O3 as 1 and compare the rate of CO2 to that.
rate of O3 = 1
MW O3 = 48
rate of CO2 = x
MW CO2 = 44
1/x = sqrt 44 / sqrt 48
1/x = 0.917
x = 1.09
So, this tells us that CO2 will diffuse 1.09 times faster than O3, or it will diffuse 9% faster