A man rows upstream 36 km and downstream 48 km taking 6 hours each time.The speed of the current is
1). 0.5 kmph
2). 2 kmph
3). 1 kmph
4). 1.5 kmph
A boat takes half time in moving a certain distance downstream than upstream. The ratio of the speed of the boat in still water and that of the current is
1). 2:1
2). 1:2
3). 4:3
4). 3:1
A man rows down a river 15 km in 3 hrs, with the stream and returns in $7\frac{1}{2}$ hrs. The rate at which he rows in still water is
1). 2.5 km/hr
2). 1.5 km/hr
3). 3.5 km/hr
4). 4.5 km/hr
The speed of a stream is 3 km/hr, and the speed of a man in still water is 5 km/ hr. The time taken by the man to swim 26 km downstream is :
1). $8\frac{2}{3}$ hrs.
2). $3\frac{1}{4}$ hrs.
3). 13 hrs.
4). $5\frac{1}{5}$ hrs.
A man swims downstream a distance of 15 km in 1 hour. If the speed of the current is 5 km/hour, the time taken by the man to swim the same distance upstream is
1). 1 hour 30 minutes
2). 45 minutes
3). 2 hours 30 minutes
4). 3 hours