If an item is sold for $Rs. 924$,there is a profit of $10\%$. What is the cost price?

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 $\%$)

Arun purchased $30 \, kg$ of wheat at the rate of $Rs. \, 11.50$ per $kg$ and $20 \, kg$ of wheat at the rate of $Rs. \, 14.25$ per $kg$. He mixed the two and sold the mixture. Approximately at what price per $kg$ should he sell the mixture to make $30 \%$ profit? (in $Rs.$)

By selling an article for $Rs. 384$,a trader gains $20 \%$. Find the cost price of the article.

$A$ vendor bought toffees at $6$ for a rupee. How many for a rupee must he sell to gain $20 \%$?

Vijay sold a watch at a gain of $5 \%$. Had he sold it for $Rs. 72$ more,he would have gained $13 \%$. Find out the cost price of the watch (in $Rs.$).