$A$ reduction of $21\%$ in the price of an item enables a person to buy $3\, Kg$ more for $₹ 100$. The reduced price of the item per $Kg$ is (in $₹$):

Successive discounts of $10 \%$,$20 \%$ and $50 \%$ will be equivalent to a single discount of .......... $\%$

$A$ shopkeeper mixes $20 \, kg$ of rice which cost him $Rs. \, 5$ per $kg$ with $35 \, kg$ of rice which cost him $Rs. \, 7$ per $kg$. Then he sells the mixture at $Rs. \, 6.5$ per $kg$. Find his total profit and percent profit.

Ram purchases a chair at $Rs. 70$ and spends $Rs. 17$ on its repair and $50$ paise on cartage. If he sells the chair at $Rs. 100$,then his approximate profit percentage will be?

$A$ shopkeeper purchases two items for $Rs. 520$. One of them is sold at a gain of $16\%$ and the other at a loss of $10\%$,thus making no profit or loss. What is the selling price of the item sold at a loss?

If a man reduces the selling price of a fan from $Rs. 400$ to $Rs. 380$,his loss increases by $2 \%$. The cost price of the fan is (in $Rs.$)