When a plot was sold for $Rs. 18700$,the owner lost $15 \%$. At what price must the plot be sold in order to gain $15 \%$?

$A$ shopkeeper earns a profit of $12 \%$ on selling a book at $10 \%$ discount on the printed price. The ratio of the cost price and the printed price of the book is

If cost price is $Rs. 150$ less than the selling price and profit is $20 \%$,then what is the selling price (in $Rs.$)?

Ravi purchases $90$ pens and sells $40$ pens at a gain of $10 \%$ and $50$ pens at a gain of $20 \%$. Had he sold all of them at a uniform profit of $15 \%$,he would have got $Rs. 40$ less. Find the cost price of each pen in $Rs$.

$A$ shopkeeper sold chairs at $Rs. 2139$ each after giving a $7 \%$ discount on the labelled price. Had he not given the discount, he would have earned a profit of $15 \%$ on the cost price. What was the cost price of each chair? (in $Rs.$)

If on selling $12$ notebooks,a seller makes a profit equal to the selling price of $4$ notebooks,what is his percent profit?