A, B and C are partners sharing in the ratio of 5 : 4 : 3. They admit D for 1/7th share. It is agreed that B would retain his original share. Sacrificing ratio will be :

A and C — 5 : 3

Old ratio between A, B & C is 5:4:3
D's share = 1/7
B will retain his original share.
As no information is given so old ratio will become the sacrificing ratio
Sacrificing ratio between A & C is =5:3