$A$ dealer marks his goods $30\%$ above his cost price and then allows a $15\%$ discount on it. What is the cost price of an article on which he gains $₹84$?

$A$ shopkeeper marks his goods at $25\%$ above his cost price and allows customers a discount of $12 \frac{1}{2}\%$ for cash. Find his $\%$ profit?

$A$ 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

Mahesh purchased $25\, kg$ of rice at $Rs. 32$ per $kg$ and $15\, kg$ of rice at $Rs. 36$ per $kg.$ He mixed the two varieties of rice and sold it at $Rs. 40.20$ per $kg.$ What is the percent profit earned (in $\%$)?

Two successive discounts of $4 \%$ on any item are equivalent to a single discount of $\%$

$A$ vendor bought toffees at $6$ for a rupee. How many for a rupee must he sell to gain $20 \%$?