61). A river is flowing with a steady speed of 4 km/h. One rows his boat downstream in the river and then returns by rowing upstream in the same river. When he returns to the starting point, the total distance covered by him is 42 km. If the return journey takes 2 h more than his outward journey, then the speed of his rowing in still water must be
| A). 12 km/h |
| B). 10 km/h |
| C). 9 km/h |
| D). 8 km/h |
|
62). In a river, the ratio of the speed of stream and speed of a boat in still water is 2 : 5. Again, ratio of the speed of stream and speed of an another boat in still water is 3 : 4. What is the ratio of the speeds of the first boat to the second boat in still water?
| A). 10 : 7 |
| B). 15 : 8 |
| C). 4 : 3 |
| D). 5 : 4 |
|
63). A, B and C are situated at the bank of river which is flowing at a constant rate. B is at an equal distance with A and C. A swimmer Avinash takes 10 h to swim from A to B and B to A. Also, he takes 4 h to swim from A to C. What is the ratio of speed of Avinash in still water and speed of stream?
| A). 5 : 3 |
| B). 3 : 5 |
| C). 2 : 5 |
| D). 1 : 2 |
|
64). A river is flowing at a speed of 5 km/h in a particular direction. A man, who can swim at a speed of 20 km/h in still water, starts swimming along the direction of flow of the river from point A and reaches another point B which is at a distance of 30 km from the starting point A. On reaching point B, the man turns back and starts swimming against the direction of flow of the river and stops after reaching point A. The total time taken by the man to complete his journey is
| A). 2 h 30 min |
| B). 3 h 12 min |
| C). 3 h 30 min |
| D). 3 h 45 min |
|
65). A man rows upstream 20 km. and downstream 25 km. taking 4 hours each time, what is the velocity of Current?
| A). \( \Large \frac{5}{8} \)km/hr |
| B). \( \Large \frac{4}{3} \)km/hr |
| C). \( \Large \frac{2}{8} \)km/hr |
| D). \( \Large \frac{1}{8} \)km/hr |
|
66). A man can row 8km/hr in still water if the river is running at 2 km/hr. it takes him one hour to row to a place and back. How far is the place?
| A). 7 km |
| B). \( \Large \frac{7.5}{2} \) km |
| C). 6 km |
| D). 12 km |
|
67). The current of a stream runs at the rate of 2km/hour. A motor boat goes 10 km. upstream and back again to the starting point in 55 minutes. Find the speed of the motor boat In still water.
| A). 22 km/hr |
| B). 11km/hr |
| C). 16 km/hr |
| D). 18 km/hr |
|
68). A boat goes 56 km. upstream in 8 hours and a distance of 36 km. down stream in 6 hours. The speed of the beat in standing water is
| A). 8.5 km/hr |
| B). 7.5 km/hr |
| C). 6.5 km/hr |
| D). None of these |
|
69). Speed of a boat in standing water is 8 km/hr. and the speed of the stream is 2.0 km/hr. A distance of 7.5 km going upstream is covered in
| A). 1 hr. 30 min. |
| B). 1 hr. 15 min. |
| C). 2 hr. |
| D). 2hr. 20 min. |
|
70). A boat travels upstream from B to A and down stream from A to B in 3 hours. If the speed of boat in still water is 9 km/hr. and the speed of current is 3 km/hr the distance between A and B (km) is
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