Question : A boy can row upstream at 12 km/hr and downstream at 23 km/hr. What is the speed of the stream?
Option 1: 3.5 km/hr
Option 2: 4.5 km/hr
Option 3: 6.5 km/hr
Option 4: 5.5 km/hr
Correct Answer: 5.5 km/hr
Solution :
Speed of the boat rowing upstream = Speed of the boat – Speed of the stream
Speed of the boat rowing downstream = Speed of the boat + Speed of the stream
Let the speed of the boat as b and the speed of the stream as s.
⇒ b – s = 12 (upstream speed)
⇒ b + s = 23 (downstream speed)
Adding the two equations,
⇒ 2b = 35
⇒ b = 17.5 km/hr
Substituting b = 17.5 km/hr into the first equation,
⇒ s = b – 12 = 17.5 – 12 = 5.5 km/hr
Hence, the correct answer is 5.5 km/hr.
Related Questions
Know More about
Staff Selection Commission Multi Tasking ...
Application | Cutoff | Selection Process | Preparation Tips | Eligibility | Exam Pattern | Admit Card
Get Updates Brochure
Your Staff Selection Commission Multi Tasking Staff Exam brochure has been successfully mailed to your registered email id “”.
