1st 10% stay in their respected committees.
2nd 15% of S joined G; Therefore, 85% went to A from S.
3rd 5% of A joined S which means 85% from A went to G.
Last 30% of G go to A. Hence, 60% go to S from G. Now we have our Stochastic Matrix.
Now, you need to diagonalize the stochastic matrix.
Solve this to obtain your long-run steady state vector.