$A$ shopkeeper expects a gain of $22 \frac{1}{2} \%$ on his cost price. If in a week,his sale was of $Rs. \,392$,what was his profit? (in $Rs$)

By selling $80$ ball pens for $₹ 140$,a retailer loses $30 \%$. How many ball pens should he sell for $₹ 104$ so as to make a profit of $30 \%$?

$A$ shopkeeper buys a toy at $Rs. 100$ and sells it at $Rs. 125$. Another shopkeeper buys the same toy at $Rs. 125$ but sells it at $Rs. 100$. What are the respective profit and loss percentages for the two shopkeepers?

If the $CP$ of $50$ items is equal to the $SP$ of $40$ items,then what is the profit or loss $\%$ (in $\%$)?

Mohit lost $18 \%$ by selling a bicycle for $Rs. 1230$. What percent shall he gain or loss by selling it for $Rs. 1600$?

If a vendor sells a coconut at $Rs. 14.4$,he makes a $10 \%$ loss. If he wants to make a $25 \%$ profit,at what price (in $Rs.$) should he sell it?