A merchant buys $4000\, kg$ of wheat, one$-$fifth of which he sells at a gain of $5$ per cent, one$-$fourth at a gain of $10 \%$, one-half at a gain of $12$ percent, and the remainder at a gain of $16$ percent. If he had sold the whole at a gain of $11$ percent, he would have made $Rs.\, 72.80$ more. What was the cost price of the crop per kg? (in $Rs.$)

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 amount of commission will he earn in two weeks if he sells $10$ notebooks and $6$ pencil boxes a day?

A fruit seller bought $240$ bananas at the rate of $Rs.\, 48$ per dozen. He sells half of them at the rate of $Rs.\,5$ per banana, $\frac{1}{6}$ th of the remaining are found to be rotten. The price per banana at which he has to sell the remaining bananas to get a profit of $25 \%$ on his entire investment is (in $Rs.$)

A dealer sold two types of goods for $Rs. 10,000$ each. On one of them, he lost $20 \%$ and on the other he gained $20 \%$. His gain or loss per cent in the entire transaction was

Profit of $Rs.\, 144000$ has to be divided among three partners Akram, Bipin and Chintan in the ratio $3 : 2: 7 .$ How much $Rs.$ does Chinatn get?