$A$ sells a good to $B$ at a profit of $10 \%$ and $B$ sells it to $C$ at a profit of $20 \%$. Find out the resultant profit percentage.

$A$ rice trader buys $16$ quintals of rice for $Rs. 5632$. $20 \%$ of the rice is lost in transportation. At what rate should he sell the remaining rice to earn a $25 \%$ profit in $Rs.$ per quintal?

$A$ vendor buys bananas at $9$ for $Rs. 8$ and sells at $8$ for $Rs. 9$. What will be the profit or loss (in $\%$)?

In these questions,two equations numbered $I$ and $II$ are given. You have to solve both the equations and mark the appropriate option.
$I$. $x^{2} = 16$
$II$. $2y^{2} - 17y + 36 = 0$

Sasha goes to a shop to buy a sofa set and a center table. She bargains for a $10 \%$ discount on the center table and a $25 \%$ discount on the sofa set. However,the manager,by mistake,interchanged the discount percentage figures while making the bill and Sasha paid accordingly. When compared to what she should have paid for her purchases,what percentage did Sasha pay extra,given that the center table costs $40 \%$ as much as the sofa set (in $\%$)?

$A$ 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 $Rs.$)