A and B share profits in the ratio 13:7. C is admitted as a partner for a 1/5 share of the profits, and the remaining profit is shared in the old ratio. What will be the new profit-sharing ratio?

Correct answer: 13:7:5

C receives 1/5 of the total profit, so 4/5 remains for A and B. Distributing this remainder in the old ratio 13:7 gives A \(\frac{4}{5}\times\frac{13}{20}=\frac{13}{25}\) and B \(\frac{4}{5}\times\frac{7}{20}=\frac{7}{25}\). C's share is \(\frac{1}{5}=\frac{5}{25}\). Therefore, the new ratio is 13:7:5. Option D incorrectly doubles the old components without making the required adjustment. Exam tip: first subtract the incoming partner's share from 1, then distribute the remainder in the old ratio.