Wednesday, 17 June 2015

19. BOAT AND STREAMS - 1 st part

1. (i) Speed of a man is 8 km/hr in still water. If the rate of the current is 3 km/h, find the effective speed of the man upstream. [Ans. (a) 5 km/hr]                                
(a) 5 km/hr    (b) 8 km/hr   (c) 6 km/hr   (d) 9 km/hr  (e) None

(ii) The speed of a boat in Still water is 2 km/hr. If its speed upstream be 1 km/hr, then the speed of the stream is [Ans. (c) 1km/hr]                
(a) 2 km/hr    (b) 3 km/hr  (c) 1km/hr   (d) 4 km/hr  (e) None

(iii) A boat goes 14 km upstream in 56 minutes. The speed of the stream is 2 km/hr. The speed of boat in still water is [Ans. (d) 17 km/hr]
(a) 6 km/hr  (b) 15 km/hr  (c) 14 km/hr  (d)17 km/hr  (e)None

(iv) The speed of a man is 7 km/hr in still water. If the rate of the current is 2 km/hr, find the effective speed of the man upstream. [Ans. (b) 5 km/hr]                                 
(a) 9 km/hr    (b) 5 km/hr  (c)14 km/hr  (d) 6 km/hr  (e) None

(v) A man’s speed with the current is 15 km/hr & the speed of the current is 2.5 km/h. The man’s speed against the current is: [Ans. (c) 10 km/hr]                           
(a) 8.5 km/hr (b)9 km/hr (c) 10 km/hr (d) 12.5 km/hr (e)None

2. (i) Speed of a swimmer is 8 km/hr in still water. If the rate of the stream is 3 km/hr, find the effective speed of the swimmer downstream. [Ans. (b) 11 km/hr]                             
(a) 6 km/hr  (b) 11 km/hr  (c)12 km/hr  (d) 9 km/hr  (e) None

(ii) The speed of a boat in Still water is 10 km/hr .If its speed downstream be 13 km/hr , then the speed of the stream is [Ans. (b)3 km/hr]
(a)1.5 km/hr (b)3 km/hr (c)11.5 km/hr (d) 5.75 km/hr (e)none

(iii) If a man goes upstream at 6 km/hr and the rate of the stream is 2 km/hr, then the man’s speed in still water is [Ans. (b) 8 km/hr]
(a) 4 km/hr    (b) 8 km/hr  (c) 2 km/hr  (d) 12 km/hr  (e) None

(iv) A boat goes 12 km upstream in 48 minutes. The speed of the stream is 2 km/hr. The speed of the boat in still water is [Ans. (c) 17 km/hr]
(a) 13 km/hr   (b) 2.25 km/hr  (c) 17 km/hr  (d)15 km/hr   (e) None

3.(i) A man can row upstream at 10 km/hr and downstream at 16 km/hr. Find the man’s rate in still water. [Ans.(a)13 km/h]
(a) 13 km/hr  (b) 18 km/hr   (c) 2 km/hr   (d) 6 km/hr  (e) None

(ii) If a man row downstream at 14 km/hr and upstream at 5 km/hr, then find man’s rate in still water. [Ans. (a) 9.5 km/hr]
(a) 9.5 km/hr  (b) 8 km/hr  (c)8.5 km/hr  (d) 9 km/hr (e)None

(iii) In one hour a boat goes 11 km along the stream and 5 km against the stream. The speed of the boat in the still water (in km/hr) is [Ans. (c) 8]    
(a) 3         (b) 5          (c) 8        (d) 9          (e) None

(iv) A boat running downstream covers a distance of 16 km in 2 hrs while for covering the same distance upstream, it takes 4 hrs. What is the speed of the boat in still water? [Ans. (b) 6 km/h]   
(a) 4 km/hr  (b) 6 km/hr  (c) 8 km/hr  (d) 9 km/hr  (e) None

(v) If a man row downstream at 16 km/hr and upstream at 11 km/hr, then find man’s rate in still water. [Ans. (b) 13.5 km/hr]
(a) 14 km/hr  (b) 13.5 km/hr  (c) 14.5 km/hr (d) 15.5 km/hr (e) None

(vi) If a man rows at the rate of 5 km/hr in still water and his rate against the current is 3.5 km/hr, then the man’s rate along  the current is [Ans. (b)6.5 km/hr]                                          
(a)8.5 km/hr  (b)6.5 km/hr (c)6 km/hr (d)4.25 km/hr (e)None

4.(i)A man can row upstream at 10 km/hr and downstream at 16 km/hr. Find the rate of the current. [Ans. (a) 3 km/hr]      
(a) 3 km/hr  (b) 8 km/hr   (c) 2 km/hr  (d) 6 km/hr   (e) None

(ii)A man can row upstream at 16 km and downstream at 27 km taking 5 hrs each time. What is the velocity of the current?  [Ans. (c) 1.1 km/hr]                                    
(a) 2 km/hr  (b) 2.1 km/hr   (c) 1.1 km/hr (d) 6 km/hr (e) None

(iii) A boat moves downstream at rate of 1 km in 7 ½ minutes and upstream at the rate of 5 km an hour. What is the velocity of the current? [Ans. (d)1.5 km/hr]                                       
(a)1.3 km/hr (b)1.2 km/hr (c)1.6 km/hr (d)1.5 km/hr (e)None

(iv) A person rows a kilometer down the stream in 10 minutes and upstream in 30 minutes. Find the velocity of the stream. [Ans. (b) 2 km/hr  ]
(a) 1 km/hr  (b) 2 km/hr  (c) 1.1 km/hr   (d) 4 km/hr  (e) None

(v) A man can row upstream at 11 km and downstream at 26 km taking 5 hrs each time. What is the velocity of the current? [Ans. (c) 1.5 km/hr]                                      
(a) 1 km/hr  (b) 1.3 km/hr (c) 1.5 km/hr (d) 2.5 km/hr (e)None

5. (i) The speed of a boat in Still water is 8 km/hr and the rate of the current is 4 km/hr. Find the distance travel downstream and upstream in 5 minutes. [Ans. (d) 1 km, 1/3 km]            
(a)2 km, ½  km (b)3 km, 2 km (c)5 km, 4 km (d) 1 km, 1/3 km]

(ii) The speed of a boat in Still water is 15 km/hr and the rate of the current is 3 km/hr. The distance travelled downstream in 12 minutes is. [Ans. (a) 3.6 km]                                           
(a) 3.6 km   (b) 2.4 km   (c) 1.2 km     (d) 1.8 km   (e) None

(iii) A boat man goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water? [Ans. (c)1 hr 15 min]
(a)40 minutes  (b)1 hr  (c)1 hr 15 min (d)1 hr 30 min (e)None

(iv) The speed of a boat in Still water is 15 km/hr and the rate of the current is 13 km/hr. The distance travelled downstream in 15 minutes is. [Ans. (a) 7 km]                            
(a) 7 km   (b) 8 km    (c) 7.5 km     (d) 7.6 km   (e) None

(v) A person can swim in still water at 4 km/hr. If the speed of the water is 2 km/hr, how many hours will the man take to swim back against the current for 6 km? [Ans. (a) 3]
(a) 3                (b) 4          (c) 4 ½         (d) 6         (e) None

(vi) 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. [Ans. (c) 4 hrs]                  
(a)  2 hrs      (b) 3 hrs        (c) 4 hrs       (d) 5 hrs          (e) None

(vii) A man can row in Stillwater at 7 km/hr and the rate of stream is 3.5 km/hr. A distance of 10.5 km in going upstream is covered in… [Ans. (c) 3 hrs]                                                
(a) 1.5 hrs     (b) 1hr      (c) 3 hrs    (d) 15 hrs     (e) None

6. (i) A man takes twice as long to row up as to row down the river. If the rate of the river is 4 km/hr, find the rate of the man in still water.                                               [Ans.(a)  12 km/hr]
(a) 12 km/hr  (b) 11 km/hr (c) 15 km/hr (d) 16 km/hr  (e) None

(ii) A man can row 4.5 km /hr in still water and he finds that it takes him twice as long to row up as to row down the river. Find the rate of the stream.                       [Ans.(b) 1.5 km/hr]
(a)2 km/hr  (b)1.5 km/hr  (c) 2.5 km/hr (d)1.75 km/hr  (e)None

(iii) A man can row 6 km /hr in still water and he finds that it takes him twice as long to row up as to row down the river. Find the rate of the stream.                          [Ans.(a) 2 km/hr]
(a) 2 km/hr  (b) 3 km/hr   (c) 1.5 km/hr   (d) 1km/hr   (e) None

 (iv) A man can row at the rate of 3.5 km/hr in Stillwater. If the time taken tom row a certain distance upstream is 2 ½ times as much as to row the same distance downstream, find the speed of the current. [Ans. (b) 1.5 km/hr]
(a)2.5 km/hr  (b)1.5 km/hr  (c) 3 km/hr  (d)1.25 km/hr (e)None

(v) A man can row 4 km /hr in still water and he finds that it takes him twice as long to row up as to row down the river. Find the rate of the stream. [Ans. (a) (1 and 1/3) km/hr  ]                      
(a) (1 and 1/3) km/hr  (b)2 km/hr  (c) 1 km/hr   (d)1.5 km/hr (e) None

(vi) A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is: [Ans. (b) 3 : 1]                                                 
(a) 2 : 1        (b) 3 : 1         (c) 3 : 2      (d) 4 : 3        (e) None

(vii) A boat running upstream takes 8 hours 48 minutes to cover a certain distance. While it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and the speed of the water current respectively?  [Ans. (c) 8 : 3]    
(a) 2 : 1        (b) 3 : 2         (c) 8 : 3      (d) 4 : 2        (e) None

1 comment: