$A$ shopkeeper sold an article at the rate of $Rs. 35$ per article and earned a profit of $40\%$. At what price should each article have been sold to earn a profit of $60\%$?

$A$ dishonest dealer professes to sell his goods at cost price but uses a weight of $960 \, g$ instead of a $1 \, kg$ weight. Find his gain $\%$. (in $\%$)

Some articles were bought at $6$ for $Rs. 5$ and sold at $5$ for $Rs. 6$. The gain percent is:

$A$ sells an article to $B$ at a gain of $20 \%$,$B$ sells it to $C$ at a gain of $10 \%$,and $C$ sells it to $D$ at a gain of $12 \frac{1}{2} \%$. If $D$ pays $Rs. 29.70$,what was the cost price for $A$? (in $Rs.$)

$A$ cycle dealer offers a discount of $10 \%$ and still makes a profit of $26 \%$. What does he pay for a cycle whose marked price is $₹ 840$? (in $₹$)

$A$ shopkeeper sells notebooks at the rate of $Rs. 457$ each and earns a commission of $4\%$. He also sells pencil boxes at the rate of $Rs. 80$ each and earns a commission of $20\%$. How much total commission will he earn in two weeks if he sells $10$ notebooks and $6$ pencil boxes a day?