A motorboat can travel at 10 km/hr. in still water it travelled 91 km downstream in a river and then returned taking at together 20 hours. Find the rate of flow of the river 

A tower standing on a horizontal plane subtends a certain angle at a point 160 cm a part from the foot of the tower. On advancing 100 meter towards the tower is found to subtend an angle twice as before. The height of tower is__

A man purchased a bedsheet for₹ 450 and sold it at a gain of 10% calculated on the selling price. The selling price of the bedsheet was 

A cylindrical well of depth 21 m with internal radius of 13 m is dug up. The mud, so detained, is spread evenly to form a platform of dimension 52 × 13.2. What is the height of the platform?

16 boys or 12 women can do a piece of work in 28 days. In how many days will the same work be done by 4 boys and 4 women, if they all work together?

Two years ago, the ratio of the age (in years) at A and B was 2:3. The ratio of their respective ages, three years from now, will be 3:5. What will be the ratio of respective ages of A and B, 6 years from now?

A, B and C enter into a partner ship with capitals in the ratio 5 : 6 :8. At the end of business term, they received the profits in the ratio 5 : 3 :12. Find the ratio of time for which they contributed their capitals?

A and B start a common business by placing their capital in the ratio of 5: 6. After 8 months A withdraws his capital. They received dividends in the ratio of 5: 9. For how long did B invest his capital?