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 goes 24km downstream in 10 hours. It takes 2 hours more to cover the same separation against the stream. What is the rate of the watercraft in still water?
Answer : A
Explanation
Speed downstream =24/10 km/hr=2.4 km/hr`Speed upstream =24/12 km/hr =2 km/hr`Speed of the boat in still water=1/2(2.4+2) km/hr=2.2 km/hr.
Q 4 - A steamer goes downstream starting with one port then onto the next in 4 hours. It covers the same separation upstream in 5 hours. In the event that the velocity of the stream is 2km/hr, the separation between the two ports is:
Answer : D
Explanation
Let the distance between the two ports be x km. Then,`Speed downstream =x/4 km/hr, Speed upstream=x/5 km/hr.`Speed of the stream=1/2(x/4-x/5).`∴ 1/2 (x/4- x/5) = 2 => x/4 -x /5 = 4 => x = 80.`Hence, the distance between the two ports is 80 km.
Q 5 - The velocity of a speedboat is that of the flow of water as 36:5. The vessel obliges the current in 5 hours 10min. It will return:
Answer : C
Explanation
Let the speed of motorboat be 36x km/hr and that of the current of water be 5x km/hr.`Speed downstream = (36x+ 5x) km/hr=41x km/hr,`Speed upstream = (36x-5x) km/hr=31x km/hr.`Distance covers downstream = (41x*31/6) km.`Distance upstream= [(41*31) x/6 * 1/31x] hrs = 41/6 hrs = 6 hrs 50 min.
Q 6 - Aman can push at 5 km/hr in still Water. It the stream is running at 1km/hr, it takes him 75 min. to line to a spot and back. How far is the spot?
Answer : B
Explanation
Speed downstream = (5+1) km/hr=6 km/hr`Speed upstream = (5-1) km/hr=4 km/hr.`Let the required distance be x km. Then,`x/6+ x/4=75/60 = 5/4 => (2x+3x) =15 => 5x = 15 => x=3.`Required distance =3km.
Q 7 - A boat goes 24km upstream and 28 km downstream in 6 hours. It goes 30km upstream and 21km downstream in 6 hours and 30 min. The rate of the vessel in still water is:
Answer : C
Explanation
Let the speed of the boat in still water be x km/hr and the speed of the stream be y km/hr.`Then, Speed upstream = (x-y) km/hr, Speed downstream = (x+y) km/hr`24/(x-y) + 28/ (x + y) = 6 => 24a + 28b = 6, where x-y = 1/a and x + y = 1/b`=>12a + 14 b = 3`30/ (x-y) + 21/ (x+y) = 13/2 => 60a + 42 b = 13`On solving (i) and (ii), we get: 28b =2 => b = 1/14 and a = 1/6`∴ (x-y=6 and x+y = 14) => x = 10, y=4.`Speed of the boat in still water=10 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 - The current of a stream keeps running at 4km 60 minutes. A boat goes 6 km and back to the beginning stage in 2hour. The rate of the boat in still water is:
Answer : C
Explanation
Let the speed in still water be x km/hr. Then,`Speed downstream = (x+ 4) km/hr, speed upstream = (x-4) km/hr.`6/(x+4) + 6 /(x-4) = 2 => 1/(x+4) +1/(x-4)=2/6 =1/3 =>(x+4)+(x-4)/x2-16=1/3 =>x2-16=6x`=> x2 -6x-16=0=> (x-8) (x+2) = 0 => x = 8.∴ Speed of boat in still water = 8 km/hr.
