Question : A man can row 12 km/hr in still water. It takes him 4 times as long to row up as to row down the river. The speed of the stream is:
Option 1: 7.2 km/hr
Option 2: 3.6 km/hr
Option 3: 9.8 km/hr
Option 4: 4.9 km/hr
New: SSC MTS 2024 Application Form OUT; Direct Link
Don't Miss: Month-wise Current Affairs | Upcoming Government Exams
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: 7.2 km/hr
Solution : Let the speed of the stream as $v$ km/hr. When the man rows downstream (with the current), his effective speed is (12 + $v$) km/hr. When he rows upstream (against the current), his effective speed is (12 – $v$) km/hr. Given that it takes him 4 times as long to row upstream as downstream, the distance travelled in both directions is the same, $\text{Time} = \frac{\text{Distance}}{\text{Speed}}$ $⇒\frac{\text{Distance}}{12 - v} = 4 \times \frac{\text{Distance}}{12 + v}$ $⇒\frac{\text{1}}{12 - v} = \frac{\text{4}}{12 + v}$ $⇒12+v = 4(12-v)$ $⇒5v=36$ $⇒v=7.2$ Hence, the correct answer is 7.2 km/hr.
Application | Cutoff | Selection Process | Preparation Tips | Eligibility | Exam Pattern | Admit Card
Question : A man can swim at a speed of 14 km/hr in still water. If he takes twice the time as long to swim opposite the flow of the river than with the flow of the river, find the rate of the stream in km/hr.
Question : A boat can row 24 km in 6 hours in still water It can row 56 km downstream and 30 km upstream in 38 hours. What is the speed of the stream?
Question : The speed of a boat in still water is 44 km/hr and the speed of a stream is 26 km/hr. Find the upstream speed of the boat.
Question : A boat takes a total of 2 hours to cover 9 km downstream and return, given that the speed of the stream is 6 km/hr. What is the speed of the boat in still water?
Question : A man rows from J to K (upstream) and back from K to J (downstream) in a total time of 15 hours. The distance between J and K is 300 km. The time taken by the man to row 9 km downstream is identical to the time taken by him to row 3 km upstream. What is the approximate speed
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile