cost price of $100$ books is equal to the selling price of $60$ books. The gain percentage or less percentage is

The profit earned by selling an article for $Rs. 832$ is equal to the loss incurred when the same article is sold for $Rs. 448.$ What should be the selling price for making $50\%$ profit? (in $Rs.$)

A shopkeeper gains $17 \%$ after allowing a discount of $10 \%$ on the marked price of an article. Find his profit percent if the article is sold at marked price allowing no discount.

If the selling price of an article is $\frac{4}{3}^{rd}$ of its cost price the profit in the transaction is $\%$

Present age of Bob is equal to Abby's age $8\, years$ ago. Four years hence, the respective ratio between Bob's age and Abby's age will be $4: 5$ at that time. What is Bob's present age? (in $years$)

Mr. Kapur purchased two toy cycles for $Rs. 750$ each. He sold these cycles, gaining $6 \%$ on one and losing $4 \%$ on the other. The gain or loss percent in the whole transaction is