The value of an article depreciates every year at the rate of $10 \%$ of its value. If the present value of the article is $Rs.\, 729$, then its worth $3\, years$ ago was (in $Rs.$)

A rice trader buys $8$ quintals of rice for $Rs.\, 3,600,10 \%$ rice is lost in transportation. At what rate should he sell to earn $15 \%$ profit in $Rs.$ per quintal ?

A dealer buys a table listed at $Rs.\,1,500$ and gets successive discounts of $20 \%$ and $10 \% .$ He spends $Rs.\, 20$ on transportation and sells at a profit of $20 \%$ Find the selling price of the table (in $Rs.$)

Two toys are sold at $Rs.\,504$ each. One toy brings the dealer a gain of $12 \%$ and the other a loss of $4 \%$. The gain or loss per cent by selling both the toys is

A man purchased $150$ pens at the rate of $Rs.\, 12$ per pen. He sold 50 pens at gain of $10 \% .$ The percentage gain at which he must sell the remaining pens so as to gain $15 \%$ on the whole outlay is........$\%$

A single discount, equivalent to a successive discount of $40 \%$ and $30 \%$ is in $\%$?