The speed of the current in a river is 6 miles per hour
Solution:
Given that,
Speed of boat in still water = 20 miles per hour
Time taken = 3 hours
Distance downstream = 78 miles
To find: Speed of current
If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then:
Speed downstream = (u + v) km/hr
Speed upstream = (u - v) km/hr
Therefore, speed downstream is given as:
[tex]\text{ speed downstream } = \frac{distance}{time} = \frac{78}{3}\\\\\text{ speed downstream } = 26 \text{ miles per hour }[/tex]
We know that,
Speed downstream = (u + v)
26 = 20 + v
v = 26 - 20
v = 6 miles per hour
Thus speed of the current in a river is 6 miles per hour
