$A$ shopkeeper loses $7 \%$ by selling a cricket ball for $Rs. 31$. For how much should he sell the ball so as to gain $5 \%$? (in $Rs.$)

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.

What profit/loss percent did Ravi earn if he purchased an item of $Rs. 5600$ and sold it at $3/4$ of its cost price?

$A$ trader sells his table at a profit of $15 \%$ and the chair at a loss of $7 \frac{1}{2} \%,$ but on the whole he gains $Rs. 50.$ If he sells the table at a loss of $7 \frac{1}{2} \%,$ and the chair at a profit of $15 \%,$ then he neither gains nor loses. Find the cost price of the table.

The percentage profit earned by selling an article for $Rs. 1920$ is equal to the percentage loss incurred by selling the same article for $Rs. 1280$. At what price should the article be sold to make $25 \%$ profit? (in $Rs.$)

$A$ shopkeeper professes to sell his goods at cost price but uses a weight of $800 \text{ g}$ instead of a $1 \text{ kg}$ weight. His profit percentage is: