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 $10 \% .$ What was the second discount rate? (in $\%$)

Due to a $20 \%$ rise in 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 $Rs.$ ?

A man sells an article at $5 \%$ above its cost price. If he had bought it at $5 \%$ less than what he had paid for it and sold it at $Rs.\, 2$ less, he would have gained $10 \% .$ The cost price of the article is (in $Rs.$)

If a banana cost is $Rs.\, 1.25$ and apple cost is $Rs .\,1 .75$ the what will be the cost of $2$ Dozen of Banana and $3$ Dozen of apple in $Rs.$?

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

An article is sold at a gain of $15 \% .$ Had it been sold for $Rs.\,27$ more, the profit would have been $20 \%$. The cost price of the article is (in $Rs.$)