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

$A$ dealer buys an article listed at $Rs. 100$ and gets successive discounts of $10\%$ and $20\%$. He spends $10\%$ of the cost price on transportation. At what price should he sell the article to earn a profit of $15\%$? (in $Rs.$)

The cash difference between the selling prices of an article at a profit of $4 \%$ and $6 \%$ is $Rs. 3$. The ratio of the two selling prices is:

$A$ sold a pen to $B$ at a profit of $20\%,$ $B$ sold the same pen to $C$ for $Rs.\,75$ thereby making a profit of $25 \% .$ Find the price at which $A$ bought the pen? (in $Rs.$)

In a certain store,the profit is $320 \%$ of the cost. If the cost increases by $25 \%$ but the selling price remains constant,approximately what percentage of the selling price is the profit?

The cost price of $100$ books is equal to the selling price of $60$ books. The gain percentage or loss percentage is: