A, B, C & D are partners sharing profits in the ratio of 2:1:2:1. C retires from the firm and the remaining partners decide to share future profits equally. What will be the gaining ratio?

0:1:1

Old ratio= 2:1:2:1
New ratio= 1:1:1
C retires means A gain= 1/3- 2/6= 0/6 = 0 means no gain
B gain= 1/3-1/6= 1/6
D gain= 1/3-1/6= 1/6
So, B & D gain equally or 1:1