Hari, the holder of 1200 shares paid the amount due on first call @ Rs 2/- per share along with second and final call which became due after 1 month…

Hari paid the first call amount late (at the time of second call payment). This means he is in arrears for the first call amount.

Calculation of Amount in Arrears:

Amount in arrears = 1200 shares × Rs 2 per share = Rs 2,400

Period of Delay:

The first call became due, but Hari paid it along with the second call which became due 1 month later.

Therefore, period of delay = 1 month

Interest Calculation:

Interest on Calls in Arrears = $\frac{\text{Amount in Arrears} \times \text{Rate} \times \text{Time (in months)}}{100 \times 12}$100×12Amount in Arrears×Rate×Time (in months)​

Using the standard rate of 10% per annum for calls in arrears:

Interest = $\frac{2400 \times 10 \times 1}{100 \times 12}$100×122400×10×1​

Interest = $\frac{24000}{1200}$120024000​ = Rs 20

The company will charge Rs 20 as interest from Hari for delaying the payment of first call by one month.