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

$A$ shopkeeper wishes to give $5 \%$ commission on the marked price of an article but also wants to earn a profit of $10 \%$. If his cost price is $₹ 95$,then the marked price is (in $₹$):

While selling a watch,a shopkeeper gives a discount of $15 \%$. If he gives a discount of $20 \%$,he earns $Rs. 51$ less as profit. What is the original price of the watch? (in $Rs$)

$A$ man sells an article at $5 \%$ above its cost price. If he had bought it at $5 \%$ less than what he had paid for it and sold it at $Rs. 2$ less,he would have gained $10 \%$. The cost price of the article is (in $Rs.$)

$A$ trader buys $500 \, kg$ of cotton for $Rs. 9,000$. $10 \%$ of this cotton is spoiled due to rain. At what rate $(Rs./ kg)$ should he sell the rest to earn $10 \%$ profit?

If eggs are bought $12$ for $Rs. 10$ and sold at $10$ for $Rs. 12$,what is the gain or loss $\%$?