Question

If the speed of a boat in still water is 7.5 km/h and the speed of the stream is 2.5 km/h . Find the total time required for the go to travel 30 km upstream and 30 km downstream

Answer 1

Heya!!

Here's ur answer...

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UPSTREAM :

Speed = speed of boat - speed of stream

Speed = 7.5 - 2.5 = 5 km/hr.

Distance = 30 km.

Time = distance /speed
Time = 30/5
Time = 6 hrs.

DOWNSTREAM :

Speed = Speed of boat + Speed of stream

Speed = 7.5 + 2.5 = 10 km/hr.

Distance = 30 km.

Time = distance / speed
Time = 30/10
Time = 3 hrs.

Total time = 6 + 3 = 9 hrs.

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Hope it may help you...

Thank you ☺️.

Answer 2

Speed of boat = 7.5 km/hr
Speed of stream = 2.5 km/hr
Downstream speed = speed of boat + speed of stream = 10 km/hr
Upstream speed = speed of boat - speed of stream = 5 km/hr

Time for Downstream = Distance/DownSpeed = 30/10 = 3 hours
Time for Upstream = Distance/speed = 30/5 = 6 hours
Total time for the whole journey = 3+6 = 9 hours.
Hope it helps