A man bought 20 dozen eggs for Rs 720. For how much should he sell per egg to earn a profit of 20%

On selling an article for Rs. 360 , a shopkeeper losses 10% . For how much (in Rs. ) he should sell the article in order to earn a profit of 25% ?

On selling 70 articles for Rs 160 a person incurred loss of 20%. How many articles he should sell for Rs 96 to earn profit of 20%.

By selling a book for 258, a bookseller gains 20%. For how much should he sell it to gain 30%?

By selling a book for 258, a bookseller gains 20%. For how much should he sell it to gain 30%?