Quants Questions : Time and Distance Set 18 – Boats

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Welcome to Online Quantitative Aptitude Section in AffairsCloud.com. Here we are creating question sample in Time and Distance(Boat) with Explanation, which is common for all the IBPS,SBI,RBI, IPPB, LIC, SSC and other competitive exams. We have included Some questions that are repeatedly asked in bank exams !!!

1. A boat takes 28 hours for travelling downstream from point A to point B and coming back to point C midway between A and B. If the velocity of the stream is 6km/hr and the speed of the boat in still water is 9 km/hr, what is the distance between A and B?
   A.115 km
   B.120 km
   C.140 km
   D.165 km
   E.150 km
   
   Answer & Explanation

   Answer – B.120 km
   Explanation :
   Downstream speed = 9+6 = 15
   Upstream speed = 9-6 = 3
   Now total time is 28 hours
   If distance between A and B is d, then distance BC = d/2
   Now distance/speed = time, so
   d/15 + (d/2)/3= 28
   Solve, d = 120 km
   
   
   
2. Speed of a man in still water is 5 km/hr and the river is running at 3km/hr. The total time taken to go to a place and come back is 10 hours. What is the distance travelled?
   A.10 km
   B.16 km
   C.24 km
   D.32 km
   E.36 km
   
   Answer & Explanation

   Answer – D.32 km
   Explanation :
   Down speed= 5+3= 8
   Up speed= 5-3=2
   Let distance travelled = X
   (X/8)+(X/2)= 10
   X= 16 km
   Total distance is 16+16=32
   
   
   
3. A boat running upstream takes 9 hours 48 minutes to cover a certain distance, while it takes 7 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?
   A.5:2
   B.7:4
   C.6:1
   D.8:3
   E.2:5
   
   Answer & Explanation

   Answer – C.6:1
   Explanation :
   Distance covered upstream in 9hrs 48 min = Distance covered downstream in 7hrs
   (X-Y) 49/5=(X+Y)7
   X/y=1/6
   
   
   
4. A boat can travel 20 km downstream in 24 min. The ratio of the speed of the boat in still water to the speed of the stream is 4 : 1. How much time will the boat take to cover 15 km upstream?
   A.20 min
   B.22 min
   C.25 min
   D.30 min
   E.35 min
   
   Answer & Explanation

   Answer – D.30 min
   Explanation :
   Down speed =20/24*60=50km/hr
   4:1 =4x:x
   Downstream speed = 4x+x=5x
   Upstream speed = 4x-x=3x
   5x= 50; x=10
   so up speed 3*10=30
   Time = 15/30*60= 30min.
   
   
   
5. A boat whose speed in 20 km/hr in still water goes 40 km downstream and comes back in a total of 5 hours. The approx. speed of the stream (in km/hr) is:
   A.6 km/hr
   B.9 km/hr
   C.12 km/hr
   D.16 km/hr
   E.18 km/hr
   
   Answer & Explanation

   Answer – B.9 km/hr
   Explanation :
   Let the speed of the stream be x km/hr. Then,
   Speed downstream = (20 + x) km/hr,
   Speed upstream = (20 – x) km/hr.
   40/20+x + 40/20-x = 5
   X = 9 approx
   
   
   
6. A boat covers a certain distance downstream in 2 hour, while it comes back in 2 1/2 hours. If the speed of the stream be 5 kmph, what is the speed of the boat in still water?
   A.40 kmph
   B.30 kmph
   C.35 kmph
   D.45 kmph
   E.None of these
   
   Answer & Explanation

   Answer – D.45 kmph
   Explanation :
   Let the speed of the boat in still water be x kmph. Then,
   Speed downstream = (x + 5) kmph,
   Speed upstream = (x – 5) kmph.
   (x + 5)*2 = (x – 5)*5/2
   X = 45 kmph
   
   
   
7. A boat running downstream covers a distance of 40 km in 5 hrs and for covering the same distance upstream it takes 10 hrs. What is the speed of the stream? 
   A.5 km/hr
   B.2 km/hr
   C.6 km/hr
   D.4 km/hr
   E.3 km/hr
   
   Answer & Explanation

   Answer – B.2 km/hr
   Explanation :
   Downstream speed = 40/5 = 8 km/hr
   Upstream speed = 40/10 = 4 km/hr
   So speed of stream = 1/2*(8-4)
   
   
   
8. A boat goes 4 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 15 km in stationary water?
   A.2 hour 15 min
   B.2 hour
   C.3hr
   D.3hr 30 min
   E.None of these
   
   Answer & Explanation

   Answer – C.3hr
   Explanation :
   Rate downstream = 1/10 * 60 = 6kmph
   Rate upstream = 4 km/hr.
   Speed in still water = ½ * 10 = 5 kmph
   Required time = 15/5 = 3 hr
   
   
   
9. A man rows to a place 40 km distant and come back in 9 hours. He finds that he can row 5 km with the stream in the same time as 4 km against the stream. The rate of the stream is:
   A.1 km/hr
   B.1.5 km/hr
   C.2 km/hr
   D.2.5 km/hr
   E.None of these
   
   Answer & Explanation

   Answer – A.1 km/hr
   Explanation :
   Speed downstream = 5/x
   Speed upstream = 4/x
   40/(5/x) + 40/(4/x) = 9
   X = ½
   So, Speed downstream = 10 km/hr, Speed upstream = 8 km/hr.
   Rate of the stream = 1/2 * 2 = 1 kmph
   
   
   
10. A man can row 8 km/hr in still water. When the river is running at 4 km/hr, it takes him 2 1/3hr to row to a place and come back. How far is the place?
    A.4 km
    B.5 km
    C.7 km
    D.10 km
    E.None of these
    
    Answer & Explanation

    Answer – C.7 km
    Explanation :
    Downstream speed = 8+4= 12 => a
    Upstream speed = 8-4= 4 => b
    Distance = a*b/(a+b) * total time (t)
    = 12*4/16 * 7/3
    = 7kms