If the CP of $4$ articles is equal to the SP of $5$ articles, find the loss per cent.

A shopkeeper sells a water geyser for $₹2370$, gaining $\frac{1}{5}$ of its cost price. Find his gain per cent.

Sameer buys a radio set for $₹440$, and sells it to Varish at a profit of $22\%$. What does Varish pay for the radio set?

A bicycle was sold at a profit of $12\%$. Had it been sold for $₹16$ more, the profit would have been $20\%$. Find the selling price of the bicycle.

By selling a pillow for $₹64$, a shopkeeper loses $36\%$ of his cost. If he sells it for $₹120$. What profit or loss would be there for him? 

A man sold two tables for $₹800$ each. on one gains $20\%$ and on the other he loses $20\%$. Find the gain or loss per cent in the whole transaction. 

Arman purchased $40 kg$ apples at $₹24 per kg$. He was able to sell half of these as $₹32 per kg$. By now $4kg$ apples had rotten. He sells the remaining apples at $₹28 per kg$. Find his gain per cent.

A farmer has bought $100$ hens for $₹4000$ sells $20$ of them at a gain of $5\%$. At what gain per cent must he sell the remaining as to gain $20\%$ on the whole?

A house was sold at a gain of $20\%$. Had it been sold for $₹3000$ more, the gain would have been $25\%$. Find the cost of the house.