Amit buys $5$ watches for $Rs. 9450$ and later sells them for $Rs. 9700$. How much profit does Amit make per watch in $Rs.$?

The profit earned by selling an article for $Rs. 900$ is double the loss incurred when the same article is sold for $Rs. 450$. At what price should the article be sold to make $25\%$ profit?

Due to a $20\%$ rise in the price of sugar,a bachelor is able to buy $1.5\, kg$ less for $Rs.\, 135$. What is the increased price of sugar per $kg$ in $Rs.$?

An article is sold at a certain fixed price. By selling it at $\frac{2}{3}$ of that price,one loses $10 \%$. The gain percent on selling it at the original price is

$A$ tradesman gives $4 \%$ discount on the marked price and gives $1$ book free for buying every $15$ books and thus gains $35 \%$. The marked price is increased above the cost price by (approx.) (in $\%$).

$A$ shopkeeper sells notebooks at the rate of $Rs. 457$ each and earns a commission of $4\%$. He also sells pencil boxes at the rate of $Rs. 80$ each and earns a commission of $20\%$. How much total commission will he earn in two weeks if he sells $10$ notebooks and $6$ pencil boxes a day?