Half of $100$ articles were sold at a profit of $20 \%$ and the rest at a profit of $40 \% .$ If all of the articles had been sold at a profit of $25 \%,$ the total profit would have been $Rs.\,100$ less than earlier profit. The cost price of each article was (in $Rs.$)

A shopkeeper purchased $70$ $kg$ of potatoes for $Rs.\, 420$ and sold the whole lot at the rate of $Rs.\, 6.5$ per $kg.$ What will be his gain percent?

A garment company declared $14 \%$ discount for wholesale buyers. Mr. Swami bought garments from the company for $Rs.$ $860$ after getting discount. He fixed up the selling price of garments in such a way that he earned a profit of $6 \%$ on original company price. What is the? approximate total selling price? (in $Rs.$)

A loss of $19 \%$ gets converted into a profit of $17 \%$ when the selling price is increased by $Rs.162.$ The cost price of the article is (in $Rs.$)

Sudeep buys two $CDs$ for $Rs.\,380$ and sells one at a loss of $22 \%$ and the other at a gain of $12 \%$. If both the $CDs$ are sold at the same price, then the cost price of two $CDs$ is (in $Rs.$)

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