Aptitude - Boats & Streams Online Quiz



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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.

Questions and Answers

Q 1 - A man can push 6 km/hr in still water. It takes him twice as long to line up as to column down the river. Find the rate of the stream.

A - 1.2 km/hr

B - 1 km/hr

C - 2 km/hr

D - 1.5 km/hr

Answer : C

Explanation

Let men's rate upstream be x km/hr`At that point, men's rate downstream = 1/2 (2x+x) km/hr = 3x/2 km/hr`And there 4; 3x/2 =6 <=> x= (2*6)/3 =4.`And there 4: 4 km/hr, rate downstream = (2*4) km/hr = 8 km/hr`Rate of stream = 1/2 (8-4) km/hr = 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.

A - 18 km/hr

B - 20 km/hr

C - 22 km/hr

D - 10 km/hr

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 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?

A - 2.2 km/hr

B - 2.8 km/hr

C - 4 km/hr

D - 4.2 km/hr.

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:

A - 50 km

B - 60 km

C - 70 km

D - 80 km

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 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:

A - 5 km/hr

B - 8 km/hr

C - 10 km/hr

D - 15 km/hr.

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 - A boat running upstream takes 8 hours 48min to cover a certain separation, while it takes 4 hour to cover the same separation running downstream. What is the proportion between the velocity of the vessel and the velocity of water flow respectively?

A - 2:1

B - 3:1

C - 8:3

D - None of these

Answer : C

Explanation

Let the speed of boat be x km /hr and speed of stream be y km/hr.`44/5 * (x-y) = 4 * (x+y) => 44(x-y) =20 (x+y) => 11 (x-y) = 5(x+y) => 6x=16y`=> x/y= 16/6 = 8/3 => x: y = 8:3.

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:

A - 4 km/hr

B - 6 km/hr

C - 10 km/hr

D - 14 km/hr.

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 - A man can push seventy five percent of a kilometer against the stream in 45/4min. what's more, return in 15/2min. The velocity of the man in still water is:

A - 2 km/hr

B - 3 km/hr

C - 4 km/hr

D - 5 km/hr

Answer : D

Explanation

Distance covered upstream in 45/4 min =3/4 km.`Distance covered upstream in 1 hr = (3/4*4/45*60) km/hr = 4 km /hr.`Distance covered upstream in 15/2 min = 3/4 km.`Distance covered upstream in 1 hr = (3/4*2/15*60) km/hr = 6 km/hr`Speed of the man in still water = 1/2 (6 +4) km/hr = 5 km/hr

Q 9 - 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:

A - 6 km/hr

B - 7.5 km/hr

C - 8 km/hr

D - 6.8 km/hr

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.

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:

A - 6 km/hr

B - 7.5 km/hr

C - 8 km/hr

D - 6.8 km/hr

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.


aptitude_boats_streams.htm

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