Under the partnership agreement between X and Y, interest on capital was to be worked out at $10\%$ per annum. At the start of the year on 1 January, the balances on X’s accounts stood at: capital $50\,000$, current $2000$ debit. On 1 July, X introduced further capital of $20\,000$. By 31 December, X’s current account balance was $20\,500$ credit. He had taken no drawings. What was X’s portion of the residual profit for the year?
- A$12\,500$
- B$15\,500$
- C$16\,500$
- D$17\,500$