A man takes 3 hours 45 minutes to row a boat 15 km downstream of a river and 2 hours 30 minutes to ...
A man takes 3 hours 45 minutes to row a boat 15 km downstream of a river and 2 hours 30 minutes to cover a distance of 5 km upstream. Find the speed of the current.
Answer/Solution
1 km/hr
Steps/Work
Explanation:
First of all, we know that
speed of current = 1/2(speed downstream - speed upstream) [important]
So we need to calculate speed downstream and speed upstream first.
Speed = Distance / Time [important]
Speed upstream =(15/3 3/4)km/hr
=15×4/15=4km/hr
Speed Downstream = (5/2 1/2)km/hr
=5×2/5=2km/hr
So speed of current = 1/2(4−2)
=1km/hr
Option A
First of all, we know that
speed of current = 1/2(speed downstream - speed upstream) [important]
So we need to calculate speed downstream and speed upstream first.
Speed = Distance / Time [important]
Speed upstream =(15/3 3/4)km/hr
=15×4/15=4km/hr
Speed Downstream = (5/2 1/2)km/hr
=5×2/5=2km/hr
So speed of current = 1/2(4−2)
=1km/hr
Option A