# 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 upstream at 6km/hr and downstream at 10 km/hr. Discover man's rate in still water and the rate of the momentum.

A - 4,5 km/hr

B - 5,6 km/hr

C - 6,8 km/hr

D - 7,9 km/hr

### Explanation

`Speed upstream =6 km/hr`Speed downstream = 10 km/hr`Rate in still water = 1/2 (10-6) km/hr. = 6km/hr`Rate of the current = 1/2 (10+6) km/hr =8 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

### 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 is paddled downstream at 15.5km/hr and upstream at 8.5km/hr. The rate of the stream is:

A - 3.5 km/hr

B - 5.75 km/hr

C - 6.5 km/hr

D - 7 km/hr

### Explanation

`Speed downstream =15.5km/hr, Speed upstream =8.5km/hr.`Speed of the stream=1/2(15.5-8.5) km/hr=3.5 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?

A - 8 km/hr

B - 12 km/hr

C - 14 km/hr

D - 10 km/hr.

### 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:

A - 5 hrs 50 min

B - 6 hours

C - 6 hours 50 min

D - 12 hrs 10 min

### 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?

A - 2:1

B - 3:1

C - 8:3

D - None of these

### 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:

A - 2 km/hr

B - 3 km/hr

C - 4 km/hr

D - 5 km/hr.

### 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

A - 2 hrs 25 mins

B - 3 hrs

C - 1 hr 24 mins

D - 2 hr 21 mins

### 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:

A - 6 km/hr

B - 7.5 km/hr

C - 8 km/hr

D - 6.8 km/hr

### 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 - Aman lines to a spot 48 km far off and in 14 hours. He finds that he can push 4km with the stream in the same time as 3km against the stream. The rate of the stream is:

A - 0.5 km/hr

B - 1 km/hr

C - 3.5 km/hr

D - 1.8 km/hr

### Explanation

`Suppose he moves 4 km downstream in x hrs.`Then, speed downstream = 4/x km/hr, speed upstream =3/x km/hr`∴ 48/ (4/x) + 48 / (3/x)    = 14 => 12x + 16x =14 => 28x = 14`=> x= 1/2.`Speed downstream = 4 / (1/2) km/hr=8 km/hr.`Speed upstream= 3/(1/2) km/hr =6km/hr.`Rate of stream = 1/2(8 - 6) km /hr=1 km/hr.`

aptitude_boats_streams.htm