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

Nutan bought a watch with $24 \%$ discount. If she pays $Rs. 779$ for that watch,then what is the marked price of the watch in $Rs.$?

Seema purchased an item for $Rs.\, 9600$ and sold it for a loss of $5\%$. From that money, she purchased another item and sold it for a gain of $5\%$. What is her overall gain or loss?

By selling $80$ ball pens for $₹ 140$,a retailer loses $30 \%$. How many ball pens should he sell for $₹ 104$ so as to make a profit of $30 \%$?

$A$ trader mixes $26 \text{ kg}$ of rice at $Rs. 20$ per $\text{kg}$ with $30 \text{ kg}$ of rice of another variety at $Rs. 36$ per $\text{kg}$ and sells the mixture at $Rs. 30$ per $\text{kg}$. His profit percent is:

$A$ shopkeeper earns a profit of $12 \%$ on selling a book at $10 \%$ discount on the printed price. The ratio of the cost price and the printed price of the book is