ABC26GN3801 · Boats and Streams

Subject: General Aptitude · Chapter: Boats and Streams · Exam: · Marks: · Difficulty:

A boatman rows to a place 45 km distant and back in 20 stream in the same time as 4 km against the stream. Fi
Answer
Answer (as printed):
Explanation
Suppose he moves 12 km downstream in x hours. Then,  12   Speed downstream =   km/hr, Speed upstream =   km/hr  x  45 45 x x 20 4 x 4 4 \ + = 20 ⇒ + = = ⇒ = ⇒ x= . (12/x ) (4/x ) 12 4 45 9 3 9 3  3 So, Speed downstream =  12 ×  km/hr = 9 km/hr,  4  3 Speed upstream =  4 ×  km/hr = 3 km/hr.  4 1 \ Speed of the stream = (9 – 3) km/hr = 3 km/hr. 2

Explanation as extracted from the printed page; notation may be imperfect.

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