$A$ shopkeeper sold a $TV$ set for $Rs. 17940$ with a discount of $8 \%$ and earned a profit of $19.6 \%$. What would have been the percentage of profit earned if no discount was offered (in $\%$)?

$A$ retailer offers the following discount schemes for buyers on an article:
$I.$ Two successive discounts of $10 \%$
$II.$ $A$ discount of $12 \%$ followed by a discount of $8 \%$
$III.$ Successive discounts of $15 \%$ and $5 \%$
$IV.$ $A$ discount of $20 \%$
The selling price will be minimum under the scheme:

If the $CP$ of $50$ items is equal to the $SP$ of $40$ items,then what is the profit or loss $\%$ (in $\%$)?

The marked price of a watch was $Rs. 720$. $A$ man bought the same for $Rs. 550.80$ after getting two successive discounts,the first being $10\%$. What was the second discount rate? (in $\%$)

$A$ shopkeeper professes to sell his goods at cost price but uses a weight of $800 \text{ g}$ instead of a $1 \text{ kg}$ weight. His profit percentage is:

$A$ trader mixes $26 \text{ kg}$ of rice at $Rs. 20$ per $\text{kg}$ with $30 \text{ kg}$ of rice of another variety at $Rs. 36$ per $\text{kg}$ and sells the mixture at $Rs. 30$ per $\text{kg}$. His profit percent is: