No. Molar Mass unit is g/mol and mass is g. Dont mix units.

You have n(tot.) = n1 + n2 express n1 and n2 as mass m1 and m2.

You have m1 + m2 = m(tot)

You have two equations with two variables. Solve for m1 and m2 , then convert to n1 and n2.

Sorry i must've confused you with my explanation cause i got the answer right - ill break down my working for you

(the value of the vessel is different fyi)

n total = (1.41x0.7888) / (0.08206 x 308.2)

n total = 0.043976622

m total = 35.283 - 32.301

m total = 2.982

Molar mass average = 2.982/0.043976622

= 67.8

Molar ratio = (Average Molar Mass - Molar mass of SO3) / (Molar Mass of SO2 - Molar Mass of SO3)

= (67.8 - 80.07) / (64.07 - 80.07)

= 0.767

This gave me the right answer (with a sig fig error which was waived)

I wouldnt have been able to do it without you so thank you