Question

A boat can go $65km$ upstream in $5$ hours and $69km$ downstream in $3$ hours. Find the speed of stream.

• A. $13km/hr.$
• B. $6km/hr.$
• C. $5km/hr.$
• D. $7km/hr.$

Answer 1

Answer: (C)

$5km/hr.$

It is given that boat can go $65$ km downstream in $5$ hours that is:

Downstream speed $=\frac{65}{5}=13$ km/hr

Also, the boat can go $69$ km downstream in $3$ hours

Upstream speed $=\frac{69}{3}=23$ km/hr

Speed of the stream $=\frac{1}{2}(23-13)=5$ km/hr

Hence, the speed of the stream is $5$ km/hr.