12
Q:

Equal distance is covered by a boat in upstream and in downstream in total 5 hours. Sum of speed of a boat in upstream and downstream is 40 km/hr. Speed of boat in still water is 600%
more than the speed of stream. Find theapproximate distance covered by boat in downstream (in km).

A) 45 B) 50
C) 55 D) 60

Answer:   B) 50



Explanation:

let speed of boat= X, speed of stream= Y
Upstream speed= X-Y
Downstream speed= X+Y
Sum of upstream & downstream= (X-Y) +(X+Y)= 2X
So, 2X= 40
X= 20 km/hr
Speed of boat : speed of stream= 600+100 :100= 7:1
So speed of Stream= 20/7 km/hr
ATQ, D/( X-Y) + D/( X+Y) = 5
D/(120/7) + D/(160/7)= 5
D= 480×5/49= 48.97 km= 50 Km(approx)

Q:

A boat covered a distance of 15 km upstream in 5 hours and a distance of 42 km downstream in 6 hours. The speed of the stream in km/h is:

 

 

A) 2 B) 3
C) 1.5 D) 2.5
 
Answer & Explanation Answer: A) 2

Explanation:
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3 722
Q:

A boat can cover a distance of 7.2 km downstream and 3.2 km upstream in 2 hours. It can also cover 1.5 km downstream and 0.6 km upstream in 24 minutes. What is the speed of the boat when going downstream (in km/h)?

 

A) 4.5 B) 6
C) 5 D) 7.5
 
Answer & Explanation Answer: B) 6

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4 664
Q:

A person can row a distance of 4 km upstream in one hour 20 minutes and can row back to the starting point in just 24 minutes. How much time(in hours) will he take to row 13 km in still water?

 

A) 2 B) 7/2
C) 3 D) 5/2
 
Answer & Explanation Answer: A) 2

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1 519
Q:

The speed of a motor boat in still water is 20 km/h .It travels 150 km downstream and then returns to the starting point. If the round trip takes a total of 16 hours, what is the speed (in km/h)of the flow of river?

 

 

A) 8 B) 6
C) 5 D) 4
 
Answer & Explanation Answer: C) 5

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4 701
Q:

The speed of a boat in still water is 12 km/h. If the boat covers a distance of 38 km upstream in 4 hours; then the speed of the stream (in km/h) is:

 

A) 6.5 B) 3.17
C) 2.5 D) 3
 
Answer & Explanation Answer: C) 2.5

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0 655
Q:

A boat can go 3.6 km upstream and 5.4 km downstream in 54 minutes, while it can go 5.4 km upstream and 3.6 km downstream in 58.5 minutes. The time (in minutes) taken by the boat in going 10 km downstream is:

 

A) 48 B) 50
C) 45 D) 54
 
Answer & Explanation Answer: B) 50

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1 1719
Q:

In a stream running at 3 km/h, a motorboat goes 12 km upstream and back to the starting point in 60 min. Find the speed of the motor boat in still water. (in km/h)

 

A) 2(2 + √17) B) 3(2 + √17)
C) 2(4 + √15) D) 3(4 + √17)
 
Answer & Explanation Answer: D) 3(4 + √17)

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3 1375
Q:

A boat at anchor is rocked by waves whose consecutive crests are 125 m apart. The velocity of the wave of the moving crests is 25 m/s. What is the frequency of the rocking of the boat?

A) 0.20 Hz B) 625 Hz
C) 250 Hz D) 100 Hz
 
Answer & Explanation Answer: A) 0.20 Hz

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2 1328