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Aptitude - Boats & Streams Online Quiz
Following quiz provides Multiple Choice Questions (MCQs) related to Boats & Streams. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.
Q 1 - A man columns 30 km downstream and 18 km upstream, taking 5 hours every time. Every time what is the speed of the current?
Answer : A
Explanation
Speed downstream = 30/5 km/hr = 6km/hr`Speed upstream = 18/5 km/hr = 3.6 km/hr`Speed of the current = 1/2 (6-3.6) km/hr = 2.4/2 km/hr = 1.2 km/hr
Q 2 - A man can push 30km upstream and 44km downstream in 10 hours. Additionally, he can push 40km upstream and 55km downstream in 13 hours. Discover the rate of flow and the current of the man in still water.
Answer : C
Explanation
Let speed upstream be x km/hr and the velocity downstream be y km/hr`At that point, 30/x+44/y=10 ... (i) and 40/x+55/y=13 ... (ii)`Increasing (ii) by 4, (i) by 5 and subtracting, we get: 10/x=2=>x=5.`Putting x=5in (i) we get 4y=44=> y=11.`∴ Speed upstream =5km/hr, speed downstream=11km/hr.`Velocity of the current =1/2(11-5) km/hr=3km/hr.`Velocity of man in still water =1/2(11+5) km/hr=8km.
Q 3 - A boat is paddled downstream at 15.5km/hr and upstream at 8.5km/hr. The rate of the stream is:
Answer : A
Explanation
Speed downstream =15.5km/hr, Speed upstream =8.5km/hr.`Speed of the stream=1/2(15.5-8.5) km/hr=3.5 km/hr
Q 4 - A watercraft covers a separation of 30km in 5/2 hrs running downstream. While returning, it covers the same separation 15/4hrs .What is the velocity of the watercraft in still water?
Answer : D
Explanation
Speed downstream = (30*2/5) km/hr=12km/hr.`Speed upstream= (30*4/15) km/hr=8 km/hr.`Speed of boat in still water=1/2(12+8) km/hr=10 km/hr.
Q 5 - The pace of a watercraft in still water is 15km/hr. It can go 30 km upstream and return downstream to the first point in 4hrs 30min. The velocity of the stream is:
Answer : A
Explanation
Let the speed of the stream be x km/hr.`Speed downstream= (15+x) km/hr, Speed upstream= (15-x) km/hr`30/ (15+x) + 30/ (15-x) = 54/60 => 30/ (15+x) + 30/ (15-x) =9/2.`=> 1/ (15+x) + 1/ (15-x) = 9/2*30= 3/20`=> (15-x) + (15+x) / (15+x) (15-x) = 3/20.`=> 3 (225-x2) = 600 => 3x2 = 75`=> x2 = 25 => x=5.`Speed of stream = 5 km/hr.
Q 6 - In a waterway, a man takes 3 hours in paddling 3 km upstream or 15km downstream. What is the rate of the current?
Answer : A
Explanation
Speed upstream =3/3 km/hr =1 km/hr.`Speed downstream =15/3 km/hr=5 km/hr.`Speed of current =1/2 (5-1) km/hr =2 km/hr
Q 7 - A vessel goes 6 km in an hour in still water. It requires thrice as much investment in covering the same separation against the current. Velocity of the current is:
Answer : C
Explanation
Speed in still water =6 km/hr.`Speed against the current =6/3 km/hr =2 km/hr`Let the speed of the current be x km/hr`6-x = 2 => x = 4 km/hr.
Q 8 - Aman can push 15/2 kms an hour in still water and he finds that it takes him twice as long to down the stream. The rate of the stream is:
Answer : B
Explanation
Let the rate of stream be x km/hr. Then,`Speed downstream = (15/2 +x) km/hr, Speed upstream = (15/2 - x) km/hr`(15/2 +x) = 2 (15/2 -x) => 3x =15/2 => x = 15/2*3 = 5/2 = 2.5`∴ Rate of stream=2.5 km/hr
Q 9 - A boatman goes 2km against the current of stream in 40 min. what's more, comes back to the same spot in 30 min. What is his rate of paddling in still water?
Answer : C
Explanation
Distance covered upstream in 40min = 4 km.`Distance covered upstream in 60 min = (4/40*60) km= 6 km`Distance covered downstream a in 30 min = 4 km`Distance covered downstream in 60 min = (4/30 * 60) km = 8 km.`Speed upstream =3 km/hr, speed downstream =4 km/hr.`Speed in still water = 1/2 (6 +8) km/hr=7 km /hr.
Q 10 - A boat sets aside half time in moving a sure separation downstream then upstream. What is the proportion between rate in still Water and rate of current and flow?
Answer : B
Explanation
Let the speed of boat in still water be u km/hr and speed of the current be v km/hr.`Rate downstream = (u+v) km/hr, Rate upstream= (u-v) km/hr.`Let the distance covered in each case be x km. Then,`2x/(u+v) = x/ (u-v) => 2 (u-v) = (u+v) => u =3v =>u/v=3/1`Required ratio = 3:1.
