Nitu has a an initial capital of Rs. 20,000. Out of
this, she invests Rs. 8,000 at 5.5% in bank A,
Rs. 5,000 at 5.6% in bank B and the remaining
amount at x% in bank C, each rate being simple
interest per annum. Her combined annual interest
income from these investments is equal to 5% of
the initial capital. If she had invested her entire initial
capital in bank C alone, then her annual interest
income, in rupees, would have been