A loan of ₹8400 taken at 10% per annum compound interest is to be cleared in two equal annual instalments, the first paid one year after the loan is taken. Each instalment (in ₹) is:

If each instalment is $x$, its present value is $x/1.1$ for the first and $x/1.21$ for the second, and these must total ₹8400: $x(10/11+100/121)=210x/121=8400$, so $x$ = ₹4840. Check: 8400 → 9240, pay 4840, leaving 4400; 4400 → 4840, paid off exactly. Halving the loan (₹4200) ignores interest altogether, while ₹4620 and ₹5082 charge one or two years of interest on the WHOLE loan even though half of it is repaid after a year.