A man buys two chairs for a total cost of $900.$ By selling one for $\frac{4}{5}$ of its cost and the other for $\frac{5}{4}$ of its cost, he makes a profit of $90$ on the whole transaction. The cost of the lower priced chair is (in $Rs.$)

A shopkeeper buys an article at $8$ for $Rs\,16$ and sells them at $9$ for $Rs\,20$. What is his gain or loss percent?

A man invests $Rs.\, 21,000$ in shares of a company. He sells one$-$third of total shares at a profit of $10 \% .$ But the remaining shares he has to sell at $5 \%$ loss. Find his overall profit or loss $\%.$

The difference between successive discounts of $40 \%$ followed by $30 \%$ and $45 \%$ followed by $20 \%$ on the marked price of an article is $Rs.\,12.$ The marked price of the article is (in $Rs.$)

If the selling price of $50$ articles is equal to the cost price of $40$ articles, then the loss or gain percent is 

A businessman allows a discount of $10 \%$ on the marked price. What percent above the cost price must he mark his goods to make a profit of $17 \% ?$