A man can row 30 km downstream and return in a total of 8 hours. If the speed of the boat in still water is four times the speed of the current, then the speed of the current is
1). 1 km/hour
2). 2 km/hour
3). 4 km/hour
4). 3 km/hour
In a fixed time, a boy swims double the distance along the current that he swims against the current. If the speed of the current is 3 km/ hr, the speed of the boy in still water is
1). 6 km/hr
2). 9 km/hr
3). 10 km/hr
4). 12 km/hr
A boat goes 6 km an hour in still water, but takes thrice as much time in going the same distance against the current.The speed of the current (in km/hour) is:
1). 4
2). 5
3). 3
4). 2
A boat moves downstream at the rate of 1 km in $7\frac{1}{2}$ minutes and upstream at the rate of 5 km an hour.What is the speed of the boat in the still water
1). $3\frac{1}{2}$ km/hour
2). $6\frac{1}{2}$ km/hour
3). 4 km/hour
4). 8 km/hour
A man rows 750 m in 600 seconds against the stream and returns in $7\frac{1}{2}$ minutes. Its rowing speed in still water is (in km/hr).
1). 5.5
2). 5.75
3). 5
4). 5.25