$A$ man bought $20$ shares of $Rs. 100$ at $4$ discount,the rate of dividend being $12 \%$. The rate of interest obtained is (in $\%$):

$A$ man bought $Rs. 20000$ of $5\%$ stock at $90$ and sold it when its price rose to $Rs. 93 \frac{3}{4}$. Find out his gain percent.

$12500$ shares, of par value $Rs.\, 20$ each, are purchased from Ram by Mohan at a price of $Rs.\, 25$ each. Find out the amount required to purchase the shares. If Mohan further sells the shares at a premium of $Rs.\, 11$ each, then find out his gain in the transaction. (in $Rs.$)

$A$ man invests $Rs. 27600$ in $4 \%$ stock at $92$. He sold $Rs. 20000$ stock when the price rose to $Rs. 96$,and sold the remaining stock when the market value fell to $Rs. 90$. How much does he gain or loss in the transaction?

The capital of a company is made up of $50000$ preferred shares with a dividend of $20 \%$ and $20000$ common shares,the par value of each type of share being $Rs. 10$. The company had a total profit of $Rs. 180000$,out of which $Rs. 30000$ were kept in a reserve fund and the remaining was distributed to shareholders. Find the dividend percentage for the common shareholders (in $\%$).

Find the income obtained by investing $Rs. 90000$ in $7 \frac{1}{2} \%$ stock at $112 \frac{1}{2}$ (in $Rs.$).