$P$ invests $Rs.\, 9100$ for $3\, months.$ $Q$ invests $Rs.\, 6825$ for $2\, months$ and $R$ $Rs.\, 8190$ for $5\, months$ in a business. If the total profit amounts to $Rs.$ $4158,$ how much profit should $Q$ get? (in $Rs.$)

Aditya purchase a book with a $20 \%$ discount on the marked price. How much $Rs.$ did he pay if the book marked was $Rs.$ $500 ?$

The marked price of a watch was $Rs.\,720.$ A man bought the same for $Rs.\, 550.80$ after getting two successive discounts, the first being $10 \% .$ The second discount rate is.......$\%$

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

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

$'A ^{\prime}$ sells a good to $'B ^{\prime}$ at a profit of $10 \%$ and $B$ sells it to $'C ^{\prime}$ at a profit of $20 \% .$ Find out the resultant profit. (in $Rs.$)