CA Foundation Exam > CA Foundation Questions > A man rowing at the rate of 5km in an hour in...
Start Learning for Free
A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:
- a)9.5 km/hr
- b)2.5 km/hr
- c)12km/hr
- d)None
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
A man rowing at the rate of 5km in an hour in still water takes thrice...
Speed of the boat in water =.5 km/hr
Let the speed of the stream be x km/hr
So, the speed of the boat upstream will be (5-x) km / hr
So, the speed of the boat downstream is (5+x) k/hr
Time given to cover 40 km upstream = 3(time taken to cover dowmstream)
⇒40/ (5-x) km/hr = 3(5+x)
⇒1/(5-x)=3(5+x)
⇒5+x=15-3x
⇒x+3x=15-5
⇒4x=10
⇒X=10/4
⇒X=5/2
∴x=2.5 km/hr
Let the speed of the stream be x km/hr
So, the speed of the boat upstream will be (5-x) km / hr
So, the speed of the boat downstream is (5+x) k/hr
Time given to cover 40 km upstream = 3(time taken to cover dowmstream)
⇒40/ (5-x) km/hr = 3(5+x)
⇒1/(5-x)=3(5+x)
⇒5+x=15-3x
⇒x+3x=15-5
⇒4x=10
⇒X=10/4
⇒X=5/2
∴x=2.5 km/hr
Most Upvoted Answer
A man rowing at the rate of 5km in an hour in still water takes thrice...
Free Test
FREE
| Start Free Test |
Community Answer
A man rowing at the rate of 5km in an hour in still water takes thrice...
Let's assume the rate at which the river flows is 'x' km/h.
Speed downstream:
When rowing downstream, the speed of the boat is equal to the sum of the speed of the boat in still water and the speed of the river.
So, the speed downstream = 5 + x km/h.
Speed upstream:
When rowing upstream, the speed of the boat is equal to the difference between the speed of the boat in still water and the speed of the river.
So, the speed upstream = 5 - x km/h.
Time taken to go downstream:
The time taken to travel a distance of 40 km downstream can be calculated using the formula:
Time = Distance / Speed
Therefore, the time taken to go downstream = 40 / (5 + x) hours.
Time taken to go upstream:
The time taken to travel a distance of 40 km upstream can be calculated using the same formula:
Time = Distance / Speed
Therefore, the time taken to go upstream = 40 / (5 - x) hours.
Given that the time taken to go upstream is three times the time taken to go downstream:
40 / (5 - x) = 3 * (40 / (5 + x))
Solving the equation:
Let's solve this equation to find the value of 'x'.
Multiply both sides of the equation by (5 - x) and (5 + x):
40 * (5 + x) = 3 * 40 * (5 - x)
200 + 40x = 3 * (200 - 40x)
200 + 40x = 600 - 120x
160x = 400
x = 400 / 160
x = 2.5 km/h
Therefore, the rate at which the river flows is 2.5 km/h, which is option 'B'.
Speed downstream:
When rowing downstream, the speed of the boat is equal to the sum of the speed of the boat in still water and the speed of the river.
So, the speed downstream = 5 + x km/h.
Speed upstream:
When rowing upstream, the speed of the boat is equal to the difference between the speed of the boat in still water and the speed of the river.
So, the speed upstream = 5 - x km/h.
Time taken to go downstream:
The time taken to travel a distance of 40 km downstream can be calculated using the formula:
Time = Distance / Speed
Therefore, the time taken to go downstream = 40 / (5 + x) hours.
Time taken to go upstream:
The time taken to travel a distance of 40 km upstream can be calculated using the same formula:
Time = Distance / Speed
Therefore, the time taken to go upstream = 40 / (5 - x) hours.
Given that the time taken to go upstream is three times the time taken to go downstream:
40 / (5 - x) = 3 * (40 / (5 + x))
Solving the equation:
Let's solve this equation to find the value of 'x'.
Multiply both sides of the equation by (5 - x) and (5 + x):
40 * (5 + x) = 3 * 40 * (5 - x)
200 + 40x = 3 * (200 - 40x)
200 + 40x = 600 - 120x
160x = 400
x = 400 / 160
x = 2.5 km/h
Therefore, the rate at which the river flows is 2.5 km/h, which is option 'B'.
|
Explore Courses for CA Foundation exam
|
|
Similar CA Foundation Doubts
Top Courses for CA FoundationView all
A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer?
Question Description
A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? for CA Foundation 2025 is part of CA Foundation preparation. The Question and answers have been prepared according to the CA Foundation exam syllabus. Information about A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for CA Foundation 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer?.
A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? for CA Foundation 2025 is part of CA Foundation preparation. The Question and answers have been prepared according to the CA Foundation exam syllabus. Information about A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for CA Foundation 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer?.
Solutions for A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for CA Foundation.
Download more important topics, notes, lectures and mock test series for CA Foundation Exam by signing up for free.
Here you can find the meaning of A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A man rowing at the rate of 5km in an hour in still water takes thrice as much time in going 40km up the river as in going 40km down. Find the rate at which the river flows:a)9.5 km/hrb)2.5 km/hrc)12km/hrd)NoneCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice CA Foundation tests.
|
|
Explore Courses for CA Foundation exam
|
|
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup