By selling cloth at $Rs.\, 9$ per meter, a shopkeeper loses $10 \% .$ Find the rate at which it should be sold so as to earn profit of $15 \%$ (in $RS.$)

By selling 80 ball pens for $Rs.\, 140$ a retailer loses $30 \%$. How many ball pens should he sell for $Rs.\, 104$ so as to make a profit of $30 \% ?$

A product when sold with $10 \%$ rebate on the listed price gave a profit of $Rs$ $70 .$ What was its cost price? (in $Rs$)

Profit earned by an organization is distributed among officers and clerks in the ratio of $5: 3 .$ If the number of officers is $45$ and the number of clerks is $80$ and the amount received by each officer is $Rs.\,25,000,$ what was the total amount of profit earned? (in $Rs.$.......$lakhs$)

A men bought apples at the rate of $8$ for $Rs.\, 34$ and sold them at the rate of $12$ for $Rs.\, 57 .$ How many apples should be sold to earn a net profit of $Rs.$ $45 ?$

A man bought apples at the rate of 6 for $Rs.\,20$ and sold them at $4$ for $Rs.\, 16.$ His estimated profit $\%$ is