Quantitative Aptitude: Boats and Streams Questions Set 4

Boats and Streams Questions for IBPS PO, IBPS Clerk, IBPS RRB, SBI, LIC, IPPB, RBI and other exams. Boats and Streams Questions Bank PO.

1. Ram goes downstream with a boat to some destination and returns upstream to his original places in 6 hours. If the speed of the boat in still water and the stream are 12km/hr and 5 km/hr respectively, then find the distance of the destination form the starting position.
   A) 25km
   B) 26.67km
   C) 33km
   D) 29.75km
   E) 20km
   
   View Answer

     Option D
   Solution:
   T = 2xD/(x^2 – y^2)
   => D = 119*6/2*12 = 29.75km
   
2. A boat travels downstream for 14km and upstream for 9km. If the boat took total of  5 hours for its journey. What is the speed of the river flow if the speed of the boat in still water is 5km/hr?
   A) 8km/hr.
   B) 2km/hr.
   C) 6km/hr.
   D) 5km/hr.
   E) 3km/hr.
   
   View Answer

     Option B
   Solution:
   Let the speed of the stream be x km/hr.
   Upward  speed = (5 – x)km/hr.
   Downward speed = (5 + x)km/hr.
   14/(5+x) + 9/(5-x) = 5
   => x = 2km/hr.
   
3. When a person is moving in the direction perpendicular to the direction of the current is 20km/hr , speed of the current is 5km/hr. Then find the speed of the person against the current?
   A) 10km/hr.
   B) 15km/hr.
   C) 30km/hr.
   D) 25km/hr.
   E) 11km/hr.
   
   View Answer

     Option A
   Solution:
   Speed of the person = 20 – 5 = 15km/hr
   Speed of the person against the current = 15 – 5 = 10km/hr.
   
4. A boat goes 6 km an hour in still water, it takes thrice as much time in going the same distance against the current comparison to the direction of the current. Find the speed of the current.
   A) 5km/hr
   B) 3km/hr
   C) 8km/hr
   D) 9km/hr
   E) 12km/hr
   
   View Answer

     Option B
   Solution:
   Let the speed of the stream be x km/hr
   speed of the still water = 6 km/hr
   Downstream speed = (6+x) km/hr
   Upstream speed = (6-x)km/hr
   Now,
   3[D/(6+x)] = D/(6-x)
   => x = 3 km/hr
5. There are two places A and B which are separated by a distance of 100k. Two boats starts form both the places at the same time towards each other. If one boat is going downstream then the other one is going upstream, if the speed of A and B is 12km/hr. and 13km/hr. respectively. Find at how much time will they meet each other.
   A) 10hrs.
   B) 4 hrs.
   C) 8hrs.
   D) 6hrs.
   E) 7hrs.
   
   View Answer

     Option B
   Solution:
   Downstream = (12+x)km/hr
   Upstream = (13-x)km/hr
   Time = Distance / Relative speed
   Relative speed = 12 + x + 13 – x  = 25 km/hr
   Time = 100/25 = 4 hours
   
6. A girl was travelling in a boat, suddenly wind starts blowing and blows her hat and started floating back downstream. The boat continued to travel upstream for 12 more minutes before she realized that her hat had fallen off. She turned back downstream and she caught her hat as soon as she reached the starting point. If her hat flew off exactly 2km from where she started. What is the speed of the water?
   A) 12km/hr
   B) 8km/hr
   C) 5km/hr
   D) 9km/hr
   E) 10km/hr
   
   View Answer

     Option C
   Solution:
   Distance = 2 km
   Time = 2 * 12 (doubles ) = 24 mins. = 2/5 hr.
   Speed = 2 / (2/5) = 5 km/hr.
   
7. A ship sails 30km of a river towards  upstream in 6 hours. How long will it take to cover the same distance downstream. If the speed of the current is (1/4)rd of the speed of the boat in still water.
   A) 2 hrs
   B) 4.5hrs
   C) 5 hrs
   D) 3.6hrs
   E) 5.5 hrs
   
   View Answer

     Option D
   Solution:
   Let x be speed of the boat and y be the speed of the current.
   Downstream speed =  x + y
   Upstream speed = x – y
   x –y = 30/6  = 5 km/hr.
   Now,
   x = 4y
   x – y = 4y – y = 3y
   => x = (20/3)km/hr and  y = (5/3)km/hr
   Therefore, x + y = (25/3) km/hr.
   Time during downstream = 90/25 =3.6 hrs.
   
8. A man can row 6km/hr in still water. If the speed of the current is 2km/hr, it takes 4 hours more in upstream than in the downstream for the same distance. Find the distance.
   A) 44km
   B) 40km
   C) 32km
   D) 50km
   E) 45km
   
   View Answer

     Option C
   Solution:
   Let the distance be D.
   Downstream speed =  8 km/hr
   Upstream speed = 4km/hr
   From the question,
   Upstream = Downstream + 4
   D/4 = D/8 + 4
   D/4 = (D + 32)/8
   D = 32 km
   
9. The speed of the motor boat is that of the current of water is 36:5 . The boat goes along with the current in 5 hours 10 minutes . How much time it will take to come back .
   A) 45/2
   B) 41/6
   C) 55/3
   D) 38/7
   E) 52/8
   
   View Answer

     Option B
   Solution:
   S1/S2 = T1/T2
   (36 + 5)/(36 – 5) = x/(31/6)
   => x = 41/6 = 6 hours 50 minutes
   
10. In a fixed time, a boy swims double the distance along the current that he swims against the current. If the speed of the current is 3km/hr. , then what is the  speed of the boy in still water ?
    A) 9 km/hr
    B) 13km/hr
    C) 15km/hr
    D) 22km/hr
    E) 10km/hr
    
    View Answer

      Option A
    Solution:
    Let the speed of boy in still water be x km/hr
    and the speed of current is given = 3 km/hr
    Downstream speed = (x+3) km/hr
    Upstream speed = (x-3) km/hr
    Let time be t hours
    (x+3)*t = 2 {(x-3)*t}
    => x = 9 km/hr