A shopkeeper sells an article at a gain of $10 \% .$ Had he sold it at a loss of $20 \%,$ its selling price would have been $Rs.\,180$ less. What is the cost price of the article? (in $Rs.$)

$'A'$ buys an article and sells it to $'B'$ at a profit of $10 \%,{ }^{\prime} B ^{\prime}$ sells it to $'C ^{\prime}$ gaining $20 \% .$ If $'C ^{\prime}$ gives $RS.\,924,$ what amount did $'A'$ give? (in $Rs.$)

If selling price is doubled, profit triples. Find the profit percent.

A shopkeeper has to sell $24\, Kg$ of sugar. He sells a part of these at a gain of $20 \%$ and the rest at a loss of $5 \% .$ If on the whole he earns a profit of $10 \%$, the amount of Sugar sold at a loss is in $Rs.$?

Albert buys $4$ $horses$ and $9$ cows for $Rs. 13400$. If he sells the horse at $10 \%$ profit and the cows at $20 \%$ profit, then he earns a total profit of $Rs.\, 1880 .$ The cost of a horse is (in $Rs.$)

Find a simple discount equivalent to a discount series of $10 \%, 20 \%$ and $25 \%$ (in $\%$)