One filling pipe P is three times faster than another filling pipe Q, if P can fill tank in 24 hours, then what is the time taken to completely fill the tank if both the pipes are opened together?

Two friends A and B invest in a business in partnership. B borrows 20% of A’s salary, combines it with 60% of his salary and invests with A, who puts all of his remaining salary. One year later the ratio of profit of A and B is 5 : 3 respectively and B returns Rs. 21000 to A which he borrowed from him. What is the difference between salary of A and B?

$$ {\sqrt{784}} × \sqrt{6.25} + 56\%\ of\ 450=?+186$$

12 × 15 + 27 – ? = 28% of 400

$$ (17)^{2} + 6 × (13)^{2}-212×6$$

In an army selection process, the ratio of selected to unselected candidates was 3 : 1. If 80 less had applied and 40 less selected, the ratio of selected to unselected candidates would have been 4 : 1. How many candidates had applied for the process? 

The rates of working of A and B are in the ratio of 2 : 3. The number of days taken by each of them to finish the work is in the ratio : 

A shopkeeper earns a profit of 15% after selling a book at 20% discount on the printed price. The ratio of the cost price and printed price of the book is :