$A$ shopkeeper buys articles at $8$ for $Rs\,16$ and sells them at $9$ for $Rs\,20$. What is his gain or loss percent?

Ram sold two horses at the same price. In one he gets a profit of $10 \%$ and in the other he gets a loss of $10 \%$. What is the overall result for Ram?

$A$ vendor bought toffees at $6$ for a rupee. How many for a rupee must he sell to gain $20 \%$?

Instead of dividing $391$ cookies among $3$ children $A, B, C$ in the ratio $\frac{1}{5}: \frac{1}{4}: \frac{1}{8}$,they were divided in the ratio $5: 4: 8$. Who gains the most and how many?

Rehaan purchased a bike for $Rs. 54,000$. He sold it at a loss of $8\%$. With that money, he again purchased another bike and sold that at a profit of $10\%$. What is his overall loss or profit?

$A$ cab driver makes a profit of $20 \%$ on every trip when he carries $3$ passengers and the price of petrol is $Rs. 30$ a litre. Find the percentage profit for the same journey if he goes with four passengers per trip and the price of petrol reduces to $Rs. 24$ a litre? (in $\%$)
(Assume that revenue per passenger is the same in both the cases.)