$A$ shopkeeper loses $7 \%$ by selling a cricket ball for $Rs. 31$. For how much should he sell the ball so as to gain $5 \%$? (in $Rs.$)

$A$ trader sold an article at a gain of $20 \%$. Had he purchased it for $40 \%$ more and sold for $Rs. 24$ less,he would have incurred a loss of $20 \%$. What is the cost price (in $Rs.$) of the article?

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?

$A$ tradesman gives $4 \%$ discount on the marked price and gives $1$ book free for buying every $15$ books and thus gains $35 \%$. The marked price is increased above the cost price by (approx.) (in $\%$).

Charging $30 \%$ above its production cost,a radio maker puts a label of $Rs. 286$ on a radio as its price. But at the time of selling it,he allows a $10 \%$ discount on the labeled price. What will his gain be? (in $Rs.$)

$A$ man purchased $120$ reams of paper at $Rs. 80$ per ream. He spent $Rs. 280$ on transportation,paid octroi at the rate of $40$ paise per ream,and paid $Rs. 72$ to a porter. In order to gain $8\%$ profit,he must sell each ream of paper for (in $Rs.$):