A sum lent at compound interest amounts to 72.8% more than itself in 3 years, interest compounded annually at a certain rate per cent per annum. What will be the compound interest (in ₹) on a sum of ₹18,000 for \(1 \frac{1}{2}\) years at the same rate, if the interest is compounded six-monthly?
1
6,897
2
5,598
3
7,654
4
5,958
5
None of the above