A man can row upstream at 12 km/h and downstream at 20 km/h. Find the man’s rowing speed in still water, and the rate of current.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 16 km/h and 4 km/h.
We know that,
Speed upstream = 12 km/hr
x - y = 12.....(1)
Speed downstream = 20 km/hr
x + y = 20 .....(2)
here, x = speed in still water and y = rate of current
Solving equation (1) and (2):
2x = 32
⇒ x = 16 km/hr
And,
y = 20 - 16 = 4 km/hr
Hence, rowing speed in still water and rate of current are 16 km/hr and 4 km/hr respectively.