If the discount of $10 \%$ is given on the marked price of a radio, the gain is $20 \%$. If the discount is increased to $20 \%,$ the gain is......$\%$

Nitin bought some oranges at $Rs.\, 40$ a dozen and an equal number at $\,30$ a dozen. He sold them at $Rs.\,45$ a dozen and made a profit of $\,480.$ The number of oranges, he bought, was

Savita buys $5$ shirts and $10$ pants for $Rs.$ $1600 .$ She sells shirts at a profit of $15 \%$ and pants at a loss of $10 \% .$ If her over all profit was $Rs.\,90$ what was the cost price of a shirt and a pant in $Rs.$?

An article is sold for $Rs.\,4950$ at a gain of $10 \% .$ What would have been the gain or loss per cent if it had been sold for $Rs$ $4275 ?$

The percentage profit earned by selling an article for $Rs.\,1920$ is equal to the percentage loss incurred by selling the same article for $Rs.\,1280.$ At what price should the article be sold to make $25 \%$ profit? (in $Rs.$)

The cost price of an article is $80 \%$ of its marked price for sale. How much percent does the tradesman gain after allowing a discount of $12 \% ?$