A boat moves 36 km from p to q in 12 hours in still water. it can row 5 km along the water and 3 km against the water. what is the speed of the stream?
Answers
Speed of the stream is 0.75 km/hr.
The relation between speed, distance, and time is given as
Speed=Distance/Time
Now the speed of the boat in the still water is calculated as
V=36/12=3 km/hr
According to the question, boat can travel 5 km along the water, and 3 km against the water in the same time.
Let the velocity of the stream is x km/hr
Than the velocity of the boat along the stream is =3+x
the velocity of the boat against the stream is =3-x
Now
=
On solving, x=0.75 km/hr
Therefore the velocity of the stream is 0.75 km/hr.
Total distance = 36 km
Total time taken = 12 hours
As per the formula, speed = distance/time
Speed = 36/12 = 3 km/hr
As per the question, the boat can easily travel for 5 km along the water and 3km if it goes against the water.
If we take the speed of such condition in stream to be x km/hr
Then speed or velocity in upstream will be 3+ x while in the downstream will be 3 – x
5/3+x = 3/3-x
5(3-x) = 3(3+x)
15 – 5x = 9 +3x
15-9 = 3x + 5x
6 = 8x
X =6/8 = 0.75km/hr