$A$ man purchased $150$ pens at the rate of $Rs. 12$ per pen. He sold $50$ pens at a gain of $10 \%$. The percentage gain at which he must sell the remaining pens so as to gain $15 \%$ on the whole outlay is........$\%$

Profit earned by an organization is distributed among officers and clerks in the ratio of $5:3$. If the number of officers is $45$ and the number of clerks is $80$ and the amount received by each officer is $Rs. 25,000$,what was the total amount of profit earned? (in $Rs.$ lakhs)

Paras Health Care made $3000$ strips of vitamin tablets at a cost of $Rs. 4800$. The company gave away $1000$ strips of tablets to doctors as free samples. $A$ discount of $25\%$ is given on the printed price. Find the ratio of profit in $Rs.$ if the price is raised from $Rs. 3.25$ to $Rs. 4.25$ per strip and if at the latter price,samples to doctors were done away with.

The marked price of an article is $Rs. 5000$. Due to a special festive offer,a certain percentage of discount is declared. Mr. $X$ availed this opportunity and bought the article at the reduced price. He then sold it at $Rs. 5000$ and thereby made a profit of $11 \frac{1}{9} \%$. The percentage of discount allowed was:

$A$ reduction of $10 \%$ in the price of rice enables a person to obtain $25 \text{ kg}$ more for $Rs. 2250$. Find the reduced price per $\text{kg}$ of the rice (in $Rs.$).

If the selling price is doubled,the profit triples. Find the profit percent.