$A$ man buys $10$ oranges for a rupee and sells $8$ oranges for a rupee. What is the profit percent?

$A$ shopkeeper gains the cost of $8$ metres of thread by selling $40$ metres of thread. Find his gain percent.

An article is sold for $Rs. 4950$ at a gain of $10 \%$. What would have been the gain or loss per cent if it had been sold for $Rs. 4275$?

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?

$A$ single discount,equivalent to a successive discount of $40 \%$ and $30 \%$ is in $\%$?

There would be a $10 \%$ loss,if rice is sold at $Rs. 54$ per $kg$. To earn a profit of $20 \%$,the price of rice per $kg$ will be (in $Rs.$)