# 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 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.

### 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.

### 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(x^{2}-4) =240x`=>11x^{2}-240x-44=0`=>11x^{2}-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?

### 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 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`=> x^{2}= 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?

### 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:

### 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:

### 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:

### 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)/x^{2}-16=1/3 =>x^{2}-16=6x`=> x^{2}-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:

### 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)/x^{2}-16=1/3 =>x^{2}-16=6x`=> x^{2}-6x-16=0=> (x-8) (x+2) = 0 => x = 8.∴ Speed of boat in still water = 8 km/hr.