Question

A man rows to a place 48 km distinct and come back in 14 hrs. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The rate of the stream is: 

a) 1 km/hr 

b) 1.5 km/hr 

c) 1.8 km/hr 

d) 3.5 km/hr

Answer 1

Correct option: a) 1 km/hr

Explanation:

Suppose he moves 4 km downstream in x hrs. 

Then speed downstream = (4/x) km ph; and speed upstream =(3/x) km ph (48/(4/x))+(48/(3/x)) =14 therefore x= ½

Speed upstream= 6 km ph, speed downstream =8 km ph Rate of the stream=1/2*(8-6) = 1 km ph