A bank offers 5% compound interest per half year. A customer deposits Rs 8000 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest is

The interest earned on 8000 from Jan to July will be $$8000 \times 5 \times \frac{1}{100}$$ (Since rate of interest is 5 % per 6 months)

= $$80 \times 5 = 400$$

Hence, 8000 will amount to 8400. He adds another 8000 to this. So the net amount becomes 8400 + 8000 = 16,400.

Now interest earned on this amount in a period of 6 months will be $$16400 \times 5 \times \frac{1}{100} = 820$$

So the final amount will be 16400 + 820 = 17220

Total money he deposited = 8000 + 8000 = 16000

Hence, amount earned via interest = 17220 - 16000 = 1220

=> Ans - (C)