An article which is marked at $Rs. 975$ is sold for $Rs. 897$. The percentage discount is?

If the cost price of $21$ watches is equal to the selling price of $18$ watches,then what would be the gain percent in this transaction?

Three successive discounts of $10 \%$,$12 \%$,and $15 \%$ are equivalent to a single discount of what percentage (in $\%$)?

$A$ dairyman pays $Rs. 6.40$ per litre of milk. He adds water and sells the mixture at $Rs. 8$ per litre,thereby making $37.5\%$ profit. The proportion of water to milk received by the customers is

The cost of an article including the sales tax is $Rs. 616$. The rate of sales tax is $10 \%$. If the shopkeeper has made a profit of $12 \%$,then the cost price of the article is in $Rs.$?

The marked price of a piano was $Rs. 15,000$. At the time of sale,there were successive discounts of $20\%$,$10\%$,and $10\%$ on it. The sale price was (in $Rs.$)