Sonal buys mangoes at the rate of $3 \, \text{kg}$ for $Rs. 21$ and sells them at $5 \, \text{kg}$ for $Rs. 50$. To earn a profit of $Rs. 102$, he must sell how many mangoes in $\text{kg}$?

$A$ shopkeeper allows a discount of $12.5 \%$ on the marked price of a certain article and makes a profit of $20 \%$. If the article costs the shopkeeper $Rs. 210$,then the marked price of the article will be (in $Rs.$)

Two-thirds of a consignment was sold at a profit of $5 \%$ and the remainder at a loss of $2 \%$. If the total profit was $Rs. 400$,what was the total value of the consignment in $Rs.$?

$A$ tradesman marks his goods $30 \%$ more than the cost price. If he allows a discount of $6 \frac{1}{4} \%$ then his gain percent is

$A$ rice trader buys $8$ quintals of rice for $Rs. 3,600$. $10\%$ of the rice is lost in transportation. At what rate should he sell the remaining rice to earn a $15\%$ profit in $Rs.$ per quintal?

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: