Defence Exam  >  Defence Questions  >  Motorboat covers a certain distance downstrea... Start Learning for Free
Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:
  • a)
    55 km/hr
  • b)
    60 km/hr
  • c)
    50 km/hr
  • d)
    75 km/hr
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
Motorboat covers a certain distance downstream in a river in 20 hours....
GIVEN:
Time taken for Downstream = 20 hours
Time taken for Upstream = 30 hours
Speed of water = 12 km/hr
FORMULA USED:
Downstream speed = speed of boat + speed of water
Upstream speed = speed of boat – speed of water
Speed = Distance/Time
CALCULATION:
Let the distance be ‘D’ km
speed of boat = x km/hour
speed of water = y km/hour
According to the question,
Downstream speed
x + y = d/20 or d = 20 (x + y)       ----(i)
Upstream speed
x – y = d/30 or d = 30(x – y)       ----(ii)
Comparing (i) & (ii)
20(x + y) = 30(x – y)
2(x + y) = 3(x – y)
2x + 2y = 3x – 3y
x = 5y
Hence, y = Speed of the current = 12 km/hour.
Speed of boat, x = 5 × 12
= 60 km/hour
View all questions of this test
Explore Courses for Defence exam
Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer?
Question Description
Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? for Defence 2024 is part of Defence preparation. The Question and answers have been prepared according to the Defence exam syllabus. Information about Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Defence 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer?.
Solutions for Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Defence. Download more important topics, notes, lectures and mock test series for Defence Exam by signing up for free.
Here you can find the meaning of Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice Motorboat covers a certain distance downstream in a river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:a)55 km/hrb)60 km/hrc)50 km/hrd)75 km/hrCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Defence tests.
Explore Courses for Defence exam
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev