An electric pump was sold at a profit of $15 \%$. Had it been sold for $Rs. 600$, the profit would have been $20 \%$. What was the former selling price in $Rs.$?

Aditya purchased a book with a $20 \%$ discount on the marked price. How much $Rs.$ did he pay if the marked price of the book was $Rs. 500$?

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)

$A$ fruit vendor buys $10$ bananas for $Rs. 14$ and sells them at $12$ for $Rs. 15$. Find his percentage gain or loss.

The difference between a discount of $35 \%$ and two successive discounts of $20 \%$ on a certain bill was $Rs$ $22$. Find the amount of the bill in $Rs$.

$A$ pair of articles was bought for $Rs. 37.40$ at a discount of $15 \%$. What must be the marked price of each of the articles?