By selling an article for $Rs. 450$,a man loses $10\%$. The gain or loss percent if he sells it for $Rs. 540$ is:

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

Aman buys $5$ laptops and $7$ computers for $Rs. 58500$. He sells the laptops at a profit of $10\%$ and computers at a profit of $16\%$ and his total gain is $Rs. 7110$. What price does he pay for a laptop? (in $Rs.$)

Two-thirds of a consignment was sold at a profit of $5 \%$ and the remainder at a loss of $2 \%$. If the total profit was $Rs. 400$,what was the total value of the consignment in $Rs.$?

At a cost of $60$ paise per article,Sarika produces $750$ articles. She sets the selling price such that if only $600$ articles are sold,she would have made a profit of $40 \%$ on the total outlay. However,$120$ articles got spoilt and she was able to sell $630$ articles at this price. Find her actual profit or loss percent as a percentage of the total outlay,assuming that the unsold articles are useless.

$A$ trader marked the selling price of an article at $10 \%$ above the cost price. At the time of selling,he allows a certain discount and suffers a loss of $1 \%$. He allowed a discount of $\%$: