Find $CP$ when $SP = Rs. 51.70$ and $\text{loss} = 12\%$.

$A$ man purchased $150$ pens at the rate of $Rs. 12$ per pen. He sold $50$ pens at a gain of $10 \%$. The percentage gain at which he must sell the remaining pens so as to gain $15 \%$ on the whole outlay is........$\%$

Rita buys an article for $Rs. 9600$. She sold it at $12\%$ loss and gets some money,and from that money,she again buys an article and this time she gets $12\%$ profit. What was the profit or loss she got from this transaction in $Rs.$?

By selling an umbrella for $Rs. 300$,a shopkeeper gains $20 \%$. During a clearance sale,the shopkeeper allows a discount of $10 \%$ on the marked price. His gain per cent during the sale is

If the selling price is tripled and the cost price is doubled,the profit would become $65 \%$. What is the present profit (in $\%$)?

Mr. Verma sold his scooter for $Rs. 10500$ at a gain of $5 \%$. Find out the cost price of the scooter (in $Rs.$).