A man sells a scooter to his friend at $10 \%$ loss. If the friend sells it for $RS.\, 4000$ and gains $20\%,$ find out the original cost price of the scooter. (in $Rs.$)

A shopkeeper sells goods at $10 \%$ loss on cost price, but uses $20 \%$ less weight. What is his profit or loss percentage?

Kunal bought a suitcase with $15 \%$ discount on the labelled price. He sold the suitcase for $Rs$ $2880$ with $20 \%$ profit on the labelled price. At what price did he buy the suitcase? (in $Rs.$)

A shopkeeper allows a discount of $12.5 \%$ on the marked price of a certain article and makes a profit of $20 \% .$ If the article costs the shopkeeper $Rs. 210$, then the marked price of the article will be (in $Rs.$)

At a cost of $60$ paise per article, Sarika produces $750$ articles. She puts the selling price such that if only $600$ articles are sold, she would have made a profit of $40 \%$ on the 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 the percentage of total outlay assuming that the unsold articles are useless.

By what fraction selling price $(S.P.)$ must be multiplied to get the cost price $(C.P.)$ if the loss is $20 \% ?$