Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 7)
7.
The speed of a boat in still water in 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is:
Answer: Option
Explanation:
Speed downstream = (15 + 3) kmph = 18 kmph.
| Distance travelled = |  |
18 x | 12 |  km = 3.6 km. |
| 60 |
Video Explanation: https://youtu.be/IDOwWUeOldQ
Discussion:
21 comments Page 2 of 3.
Naresh said:
1 decade ago
Speed of the boat in still water (b) = 15 kmph.
Speed of the Current/Stream (s) = 3 kmph.
Speed of downstream (d) = b + s ==> 15 + 3 kmph ==> 18 kmph.
So,
It can travel 18 km in 1 hour.
So,
How many km it can travel in 12 min?
1 hour ====> 18 km.
12/60 hour ====>?
Do cross multiplications, then we get 18*1/5==>3.6.
Speed of the Current/Stream (s) = 3 kmph.
Speed of downstream (d) = b + s ==> 15 + 3 kmph ==> 18 kmph.
So,
It can travel 18 km in 1 hour.
So,
How many km it can travel in 12 min?
1 hour ====> 18 km.
12/60 hour ====>?
Do cross multiplications, then we get 18*1/5==>3.6.
(1)
NANDINI said:
1 decade ago
12/60 = 0.2.
18*0.2 = 3.6.
18*0.2 = 3.6.
Debasis said:
1 decade ago
How to calculate distance traveled = (18*12/60)?
Kavya mareedu said:
1 decade ago
Thanks goutham.
Gautam said:
1 decade ago
Use the formula= if the speed of a boat in still water is U km/hr and the speed of the stream is V km/hr, then
speed down stream = (u+v)km/hr
(15+3)km/hr = 18 km/hr
Distance travelled = (18 x 12/60)=3.6km ANSWER
[60 is here because 1 minute=60seconds]
speed down stream = (u+v)km/hr
(15+3)km/hr = 18 km/hr
Distance travelled = (18 x 12/60)=3.6km ANSWER
[60 is here because 1 minute=60seconds]
Angu said:
1 decade ago
Thanks bindu
Bindu said:
1 decade ago
Rate of current=1/2(downstream speed- upstream speed)
ie=1/2[(U+V)-(U-V)]
=1/2(U+V-U+V)
=2V/2
=V
SO RATE OF CURRENT = V(SPEED OF STREAM)
ie=1/2[(U+V)-(U-V)]
=1/2(U+V-U+V)
=2V/2
=V
SO RATE OF CURRENT = V(SPEED OF STREAM)
Sanjana said:
1 decade ago
Why we add current rate with speed?
Nagarjun said:
1 decade ago
They have specified as downstream so we have to add.
Brajendra said:
2 decades ago
why we add current rate with speed of still water??it has to
substract
substract
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