If $5 \%$ more is gained by selling an article for $Rs.\, 350$ than by selling it for $Rs$ $340,$ the cost of the article is......$\%$

Nisha bought a number of oranges at $2$ for a rupee and an equal number at $3$ for a rupee. To make a profit of $20 \%$ she should sell a dozen for (in $Rs.$)

A shopkeeper sold one$-$third of his goods at a loss of $15 \% .$ To get a profit of $10 \%$ on the whole transaction, he should sell the remaining articles at a profit of in $\%$

A trader mixes $26\, kg$ of rice at $Rs.\, 20$ per $kg$ with $30\, kg$ of rice of another variety at $Rs.\, 36$ per $kg$ and sells the mixture at $Rs$ $30$ per $kg.$ His profit percent is

The cost price of $6$ pens is equal to the selling price of $4$ pens. Find the profit percent.

A fruit-seller buys $x$ guavas for $Rs.\, y$ and sells $y$ guavas for $Rs.\, x .$ If $x>y,$ then he made