# 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(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 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 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 - 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 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 - A motor boat in still water travels at a speed of 36 kmph. It goes 36 km upstream in 1 hr 45 mins. The time taken by it to cover the same distance downstream will be

### Answer : C

### Explanation

Upstream Speed of motor boat = 56/1 hr 45 min = 32 kmph`Speed of the motor boat in still water = 36 kmph`Speed of the boat in still water = 1/2*(Downstream Speed + Upstream Speed)`36 = 1/2(d + 32)`Downstream Speed (d) = 40 km/hr``t = Distance/speed = 40/36 = 7/5 hr = 1 hr 24 mins

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 1 km/hr .A speedboat goes 35km upstream and back again to the beginning stage in 12 hours . The rate of the speedboat in still water is:

### Answer : A

### Explanation

Let the still water be x km/hr.`Speed downstream =(x+1) km/hr Speed upstream =(x-1) km/hr.`35/(x-1) + 35/(x+1) = 12 =>35[(x+1) + (x-1)] = 12 (x^{2}-1)`=> 12x^{2}-70x -12=0=> 12x^{2}-72x + 2x -12=0`=> 12x (x- 6) +2 (x - 6) = 0 =>(x-6) (12x + 2) = 0 => x=6`∴ Speed of boat in still water is 6 km/hr.