Sardar Singh bought $200$ dozen oranges at $Rs. 10$ a dozen. He spent $₹500$ on transportation. He sold them at $Rs. 1$ each. What was his profit or loss percent?

In these questions,two equations numbered $I$ and $II$ are given. You have to solve both the equations and mark the appropriate option.
$I.$ $3x^2 - 13x + 12 = 0$
$II.$ $2y^2 - 15y + 28 = 0$

$A$ vendor bought toffees at $6$ for a rupee. How many for a rupee must he sell to gain $20 \%$?

$A$ man invests $Rs. 21,000$ in shares of a company. He sells one-third of the total shares at a profit of $10\%$. However,he has to sell the remaining shares at a $5\%$ loss. Find his overall profit or loss percentage.

The market price of an article is $Rs. 100$. If the article is sold at a discount of $10 \%$,then $35 \%$ profit is realized. How much loss or profit will be made if it is sold for $Rs. 30$ less than the market price?

$A$ shopkeeper marks his goods at $40 \%$ above their cost price. He is able to sell $\frac{3}{4}$ of his goods at this price,and the remaining at $40 \%$ discount. Assuming that the shopkeeper is able to sell all the goods he buys,find his overall gain or loss percentage.