Answer:
The boat traveling at 24 kph when John goes downstream.
Step-by-step explanation:
We are given the following in the question:
John has a boat that will travel at the rate of 15 kph in still water.
Let x be the speed of the current.
Speed of boat in upstream
Speed of water in downstream
Relation:
We have to find the speed of boat in downstream.
Time to travel upstream for 35 km = Time to travel 140 km downstream
Thus, speed of current is 9 kph.
Speed of boat in downstream = 15 + 9 = 24 kph.
Thus, the boat traveling at 24 kph when John goes downstream.