Two discounts of $40 \%$ and $20 \%$ are equal to a single discount of what percentage?

$A$ shopkeeper purchased $245$ pieces of an article at $Rs. 30$ per piece. He spent $Rs. 980$ on transport and $Rs. 1470$ on packing the articles. He sold the articles at the rate of $Rs. 50$ per piece. What is the percent profit earned?

$A$ shopkeeper purchased a chair marked at $₹ 600$ at two successive discounts of $15 \%$ and $20 \%$. He spent $₹ 28$ on transportation and sold the chair for $₹ 545$. His gain percent was: (in $\%$)

If a man reduces the selling price of a fan from $Rs. 400$ to $Rs. 380$,his loss increases by $2 \%$. The cost price of the fan is (in $Rs.$)

$A$ tradesman gives $4 \%$ discount on the marked price and gives one article free for buying every $15$ articles and thus gains $35 \%$. The marked price is approximately how much percent above the $CP$?

$A$ shopkeeper marks his goods $20 \%$ above $CP$ but allows $30 \%$ discount for cash. His net loss is in $\%$?