To go a distance of 144 upstream, a rower takes 12 hours while it takes her only 9 hours to row the same distance downstream. What is the speed of the stream?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 2 km/h
Given that
A rower takes 12 hours to cover 144 km upstream
A rower takes 9 hours to cover same 144 km downstream
Let speed of stream be y and the rower speed be x
So, The downstream speed (x + y) = 144/9 = 16 km/h ....(1
The upstream speed (x - y) = 144/12 = 12 km/h ....(2
According to the question
Equation 1 - Equation 2
2y = 4
y = 2 km/h