Amit purchased $13$ chairs for $Rs. 115$ each and sold all of them for $Rs. 1220$. Find the profit or loss on the transaction.

Seema sells a pen to Sapna at a profit of $25 \%$. Sapna sells it to Asha at a profit of $10 \%$ and Asha sells it to Kavita at a profit of $5 \%$. If Asha sells it for $Rs.\,231$,find the cost price at which Seema bought the pen? (in $Rs.$)

$A$ man bought $500$ metres of electronic wire at $50$ paise per metre. He sold $50 \%$ of it at a profit of $5 \%$. At what percent should he sell the remainder so as to gain $10 \%$ on the whole transaction?

$A$ man purchased some eggs at $3$ for $Rs. 5$ and sold them at $5$ for $Rs. 12$. Thus,he gained $Rs. 143$ in all. The number of eggs he bought is:

$A$ discount series of $10 \%$,$20 \%$,and $40 \%$ is equal to a single discount of.......$\%$

The cost price of an article is $64 \%$ of the marked price. Calculate the gain percent after allowing a discount of $12 \%$.