A sells an article to $B$ at a gain of $20 \%$ and $B$ sells it to $C$ at a gain of $10 \%$ and $C$ sells it to $D$ at a gain of $12 \frac{1}{2} \% .$ If $D$ pays $Rs.\, 29.70,$ then $A$ purchased the article for (in $Rs.$)

A trader marked his goods at $20 \%$ above the cost price. He sold half the stock at the marked price, one quarter at a discount of $20 \%$ on the marked price and the rest at a discount of $40 \%$ on the marked price. His total gain is in $\%$?

The profit earned by selling an article for $Rs.\, 900$ is double the loss incurred when the same article is sold for $Rs.$ $450 .$ At what price should the article be sold to make $25 \%$ profit in $Rs.$?

A man bought $500$ metres of electronic wire at $50$ paise per metre. He sold $50 \%$ of it at a profit of $5 \%$ At what percent should he sell the remainder so as to gain $10 \%$ on the whole transaction?

The printed price of an article is $40 \%$ higher than its cost price. Then the rate discount so that he gains $12 \%$ profit is………$\%$