A fuel has the following composition on a molar basis: 40.0% CH4,
24.0% C2H4, 16% C3H8, 10% CO2, 10% H2O. What is the composition of the fuel on a dry
basis? What is the composition of the fuel on a mass basis? What is the average molecular
weight of the fuel? [Relative atomic masses: O = 16, C = 12, H = 1]

I worked out the compistion on a dry basis,

 CH_{4} = \frac{40}{90} \times 100 = 44.44mol\% and than the same for each one, excluding water.

How do I work out the composition of the fuel on a mass basis?

thank you.