Find out the income percent on $10 \%$ debentures of par value $Rs.\, 120$ available in the market for $Rs.\, 150$. (in $\%$)

$A$ started a business. After $4$ months from the start of the business,$B$ and $C$ joined. The respective ratio between the investments of $A, B$,and $C$ was $4: 6: 5$. If $A$'s share in the annual profit was $Rs. 250$ more than $C$'s share,what was the total annual profit earned? (in $Rs.$)

$A$ man buys $Rs. 50$ shares in a company which pays $10\%$ dividend. If the man gets $12.5\%$ on his investment,at what price did he buy the shares? (in $Rs.$)

Find the annual dividend received by Nishita from $1200$ preferred shares and $3000$ common shares,both of par value $Rs. 50$ each,if the dividend paid on preferred shares is $10 \%$ and a semi-annual dividend of $3 \frac{1}{2} \%$ is declared on common shares. (in $Rs.$)

Meena bought $Rs. 36000$ of $7\frac{1}{2} \%$ stock at $92$ and sold it when its price rose to $Rs. 93 \frac{3}{4}$. Find out her gain percent.

How many shares of market value $Rs. 25$ each can be purchased for $Rs. 12750$,given that the brokerage is $2\%$?