What is the purpose of calculating gaining ratio?

Dheena, Surya and Janaki are partners sharing profits and losses in the ratio of 5:3:2. On 31.3.2018, Dheena retired. On the date of retirement, the books of the firm showed a reserve fund of Rs. 50,000. Pass journal entry to transfer the reserve fund.

Kayal, Mala and Neela are partners sharing profits in the ratio of 2:2:1. Kayal retires and the new profit sharing ratio between Nila and Neela is 3:2. Calculate the gaining ratio.

Ramu, Somu, Gopu are partners sharing profits in the ratio of 3 : 5 : 7. Gopu retires and the share is purchased by Ramu and Somu in the ratio of 3 : 1. Find the new profit sharing ratio and gaining ratio

Mani, Gani and Soni are partners sharing the profits and losses in the ratio of 4:5:6. Mani retires from the firm. Calculate the new profit sharing ratio and gaining ratio.