$A$ shopkeeper purchases two items for $Rs. 520$. One of them is sold at a gain of $16\%$ and the other at a loss of $10\%$,thus making no profit or loss. What is the selling price of the item sold at a loss?

Charging $30 \%$ above its production cost,a radio maker puts a label of $Rs. 286$ on a radio as its price. But at the time of selling it,he allows a $10 \%$ discount on the labeled price. What will his gain be? (in $Rs.$)

Ram purchased a computer set for $Rs. 12500$ and spent $Rs. 300$ on transportation and $Rs. 800$ on installation. At what price should he sell it to earn an overall profit of $15\%$? (in $Rs.$)

The $CP$ of $19$ articles is equal to the selling price $(SP)$ of $15$ articles. What is the gain percentage?

$A$ man gains $20 \%$ by selling an article for a certain price. If he sells it at double the price,what will be the percentage of profit (in $\%$)?

$A$ 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.)