Oil equal to $20 \%$ of the weight of ground nut is extracted in a mill. The matter left after extraction is sold as cattle feed at the rate of $Rs.\, 12.5$ per $kg$. The ground nuts are bought at $Rs.$ $20$ per $kg.$ the processing cost is $Rs.\, 5$ per $kg$. At what price $(Rs.$ per $kg$ ) should the oil be sold to earn $20 \%$ profit on total costs (Total cost $=$ cost of groundnuts and processing costs)?

A person bought a horse and a carriage for $Rs.\,20000.$ Later, he sold the horse at $20 \%$ profit and the carriage at $10 \%$ loss. Thus, he gained $2 \%$ in the whole transaction. The cost price of the horse was (in $Rs.$)

The list price of an article at a showroom is $Rs.\, 2000$ and it is being sold at successive discounts of $20 \%$ and $10 \% .$ Its net selling price will be (in $Rs.$)

If the $CP$ of $50$ items is equal $SP$ of $40$ items then what is the profit or loss $\% ?$

A dealer buys a table listed at $Rs.\,1,500$ and gets successive discounts of $20 \%$ and $10 \% .$ He spends $Rs.\, 20$ on transportation and sells at a profit of $20 \%$ Find the selling price of the table (in $Rs.$)

A discount series of $10 \%, 20 \%$ and $40 \%$ is equal to a single discount of.......$\%$