Boats and Stream

71 A woman takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. What is the ratio of the speed of the boat (in still water) and the stream?

72 The speed of a boat in still water in 22 km/hr and the rate of current is 4 km/hr. The distance travelled downstream in 24 minutes is:

73 A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:

74 A boat can travel with a speed of 22 km/hr in still water. If the speed of the stream is 5 km/hr, find the time taken by the boat to go 54 km downstream:

75 A boat running downstream covers a distance of 22 km in 4 hours while for covering the same distance upstream, it takes 5 hours. What is the speed of the boat in still water?

76 A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?

77 A boat takes 20 hours for travelling downstream from point X to point Y and coming back to a point Z midway between X and Y. If the velocity of the stream is 4 km/hr and the speed of the boat in still water is 12 km/hr, what is the distance between X and Y?

78 The speed of a boat in still water is 12 km/hr and the rate of current is 4 km/hr. The distance travelled downstream in 15 minutes is:

79 A boat takes 90 minutes less to travel 36 miles downstream than to travel the same distance upstream. If the speed of the boat in still water is 10 mph, the speed of the stream is:

80 A man can row at 5 kmph in still water. If the velocity of current is 1 kmph and it takes him 1 hour to row to a place and come back, how far is the place?