# 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.

A - 1.2 km/hr

B - 1 km/hr

C - 2 km/hr

D - 1.5 km/hr

### 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 - A man can push 30km upstream and 44km downstream in 10 hours. Additionally, he can push 40km upstream and 55km downstream in 13 hours. Discover the rate of flow and the current of the man in still water.

A - 4,5 km/hr

B - 5,6 km/hr

C - 3,8 km/hr

D - 7,9 km/hr

### Explanation

`Let speed upstream be x km/hr and the velocity downstream be y km/hr`At that point, 30/x+44/y=10 ... (i) and 40/x+55/y=13 ... (ii)`Increasing (ii) by 4, (i) by 5 and subtracting, we get: 10/x=2=>x=5.`Putting x=5in (i) we get 4y=44=> y=11.`∴ Speed upstream =5km/hr, speed downstream=11km/hr.`Velocity of the current =1/2(11-5) km/hr=3km/hr.`Velocity of man in still water =1/2(11+5) km/hr=8km.`

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 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?

A - 2.5 km/hr

B - 3.5 km/hr

C - 4.5 km/hr

D - 4.2 km/hr.

### 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:

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 - In a waterway, a man takes 3 hours in paddling 3 km upstream or 15km downstream. What is the rate of the current?

A - 2 km/hr

B - 4 km/hr

C - 6 km/hr

D - 9 km/hr.

### Explanation

`Speed upstream =3/3 km/hr =1 km/hr.`Speed downstream =15/3 km/hr=5 km/hr.`Speed of current =1/2 (5-1) km/hr =2 km/hr`

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.

### 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 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 - A boatman goes 2km against the current of stream in 1 hours and goes 1 km along the current in 10 min. To what extent will he takes to go 5km in stationary water?

A - 40 min

B - 1 hr

C - 1 hr 15 min

D - 1 hr 30min

### Explanation

`Speed upstream =2km/hr, Speed downstream = 6 km/hr.`Speed in stationary water = 1/2 (6 + 2) km/hr = 4 km/hr.`Time taken to cover 5 km in stationary water = (1/4 *5) = 1 hr 15 min.`

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:

A - 6 km/hr

B - 7 km/hr

C - 8.5 km/hr

D - 8 km/hr

`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 (x2-1)`=> 12x2 -70x -12=0=> 12x2-72x + 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.`