100+ Boats and Streams Problems with Solutions Pdf - 2

 Question: 1

A man can row upstream at 10 kmph and downstream at 18 kmph. Find the man’s rate in still water?

(A) 4 kmph

(B) 10 kmph

(C) 12 kmph

(D) 14 kmph

View Answer

Ans: D

Speed of boatman in still water

= 

1

2

(Ratedownstream+Rateupstream)

= 

1

2

(18+10) = 

28

2

 = 14 kmph.

Question: 2

A man can row with the stream at 7 Km/h and against the stream at 3 Km/h. His speed in still water is

(A) 5 Km/h

(B) 7 Km/h

(C) 8 Km/h

(D) 9 Km/h

View Answer

Ans: A

Speed of the man upstream = 7 Km/h.

Speed of the man downstream = 3 Km/h.

∴ Speed of the man in still water = 

1

2

 (Downstream speed + Upstream speed)

= 

1

2

(7+3) = 5 Km/h.

Question: 3

A man can row upstream at 8 kmph and downstream at 13 kmph. The speed of the stream is

(A) 2 km / hr

(B) 2.5 km / hr

(C) 4.5 km / hr

(D) 5 km / hr

View Answer

Ans: B

Speed of stream = 

1

2

(13–8) kmph = 2.5 kmph.

Question: 4

A man rows, downstream 32 km upstream. If he takes 6 hours to cover each distance, then the velocity (in kmph) of the current is

(A) 1

(B) 1.5

(C) 1.5

(D) 2

View Answer

Ans: C

Rate downstream = (

32

6

) kmph

Rate upstream = 

14

6

 = 7 kmph.

∴ Velocity of current = 

1

2

(

32

6

–

14

6

) kmph = 

3

2

 kmph = 1.5 kmph.

Question: 5

A boat can travel with a speed of 13 km / hr in still water. If the speed of the stream is 4 km / hr, find the time taken by the boat to go 68 km downstream.

(A) 2 hours

(B) 3 hours

(C) 4 hours

(D) 5 hours

View Answer

Ans: C

Speed downstream = (13 + 4) km/hr = 17 km/hr.

Time taken to travel 68 km downstream = (

68

17

) hrs = 4 hrs.