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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 - In a stream running at 2 km/hr, a speedboat goes 10km upstream and back again to the beginning stage in 55 min. discover the velocity the speedboat in still water.

Answer : C

Explanation

Let the pace of the speedboat in still water be x km/hr.`Speed downstream =(x+2) km/hr, speed upstream =(x-2) km/hr.`∴ 10/(x-2) +10/(x+2) =55/60=>1/(x-2) +1/(x+2) =55/600=11/120`=> (x+2) +(x-2)/(x-4) =11/120=>11(x²-4) =240x`=>11x²-240x-44=0`=>11x²-242x+2x-44=0`=> 11x(x-22) +2(x-22) =0`=>(x-22) (11x+2) =0=> x=22.`Velocity of speedboat in still water=22km/hr.

Q 3 - A boat running downstream covers 24kms in 4 hours, while for covering the same separation upstream it takes 6 hours. What is the velocity of the watercraft in still water?

Answer : B

Explanation

Speed downstream =24/4km/hr=6 km/hr.`Speed upstream =24/6 km/hr=6 km/hr.`Speed of the boat in still water=1/2(6+4) km/hr=5 km/hr.

Q 4 - A boat running downstream covers a separation of 10km in 2 hours .While returning upstream the boat takes 5 hours to cover the same separation. In the event that the velocity of the current and flow is 1.5 kmph, what is the speed of the boat in still water?

Answer : B

Explanation

Speed downstream =10/2 km/hr=5 km/hr.`Speed upstream =10/5 km/hr = 2 km/hr.`Speed of boat in still water = 1/2 (5+2)km/hr=3.5km/hr.

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.

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