Old ratio (R, S and M) = 2:2:1
M retires from the firm
His profit share = 1/5
M’s share taken by R and S in the ratio of 1:2
Share taken by R = 1/5 X 1/3 = 1/15
Share taken by S = 1/5 X 2/3 = 2/15
New ratio = Old ratio + Share acquired from M
R’s new share =2/5 + 1/15 = 6/15 + 1/15 = 7/15
S’s new share = 2/15 + 2/15 = 6/15 +2/15 = 8/15
New profit (R and S) = 7 : 8