A trader had $1200\, kg$ of rice. He sold a part of it at $5 \%$ profit and the rest at $11 \%$ profit, so that he made a total profit of $7 \%$. How much (in $kg$ ) rice did he sell at $5 \%$ profit?

A shopkeeper sold some articles at $Rs.\,35$ per piece and gained $40 \% .$ What would be the selling price of each article to earn $60 \%$ profit? (in $Rs.$)

On a $Rs.\,10,000$ payment order, a person has a choice between three successive discounts of $10 \%, 10 \%$ and $30 \%$ and three successive discounts of $40 \%, 5 \%$ and $5 \% .$ By choosing the better offer, he can save in $Rs.$?

Ram purchased a Computer set of $Rs.\, 12500$ and spent $Rs.\,300$ on transportation and $Rs.\, 800$ on installation. At what price should he sell it so as to earn an overall profit of $15 \% ?$ (in $Rs.$)

By selling a fan for $Rs.\,1900$ a man has a loss of $5 \%$, then at what price (in $Rs.$) should he sell the fan to gain $20 \% ?$

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