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 manufacturer sells an article to a wholesale dealer at a profit of $10 \%$. The wholesale dealer sells it to a shopkeeper at $20 \%$ profit. The shopkeeper sells it to a customer for $Rs.\, 56,100$ at a loss of $15 \%$. Then the cost price of the article to the manufacturer is (in $Rs.$)

On an article the profit is $210 \%$ of the cost price. If the cost price increase by $40 \%$ but the selling price remains constant, approximately what percent of selling price will be the profit?

The cost price of $20$ articles is the same as selling price of $x$ articles. If the profit is $25 \%,$ then the value of $x$ is

Meenal purchased a car for $Rs.\, 2,50,000$ and sold it for $Rs.\, 3,48,000 .$ What is the per cent profit she made on the car?

A fruit-seller buys $x$ guavas for $Rs.\, y$ and sells $y$ guavas for $Rs.\, x .$ If $x>y,$ then he made