Boats and Stream math is one
of the important topic in bank exam questions as well as in SSC exams. Timing
plays an important role in competitive exams both bank exams and SSC exams.
Boats and Stream math questions are one of the easiest problems that we usually
miss in Competitive exams.
Here i will provide you all type of shortcut tricks
on boats and stream questions come in competitive exams like bank exams. Not
just stopped at shortcut tricks on boats and stream, here you will be provided with all
basic math formulas on boats and stream and also basic concepts.
To the readers of
this blog, please go through all the boat and stream formulas, basic concepts
and short tricks on boat and stream problems. Based on banking exams questions
some difficult problems with solutions for bank exams have also been given here.
Basic Concepts:
Downstream: Downstream (D) is calculated by adding up the boat's
speed running in the same direction with that of the current.
∴ D = Boat's Speed (B) + Speed of the Current (S)
Upstream: Upstream (U) is calculated by subtracting the
speed of the current from the speed of the Boat running in the opposite
direction of the current.
∴ U = Boat's Speed (B) -
Speed of the Current (S)
Boat's speed in still water: (Downstream + Upstream)/2
Speed of Stream: (Downstream - Upstream)/2
Quick Formulas: Click here
The formulas are always
important for faster calculations and find out answers quickly. But here, using
basic concepts problems or questions on boats and stream are being tried to
solve without remembering formulas.
Example:
- Rajesh can row 12 km/h in still water. It takes him twice as long to row up as to row down the river. Find the rate of stream?
Answer: Let's consider Rajesh as a boat (B) who's
speed is 12 km/h.
We know that there is an
inverse relation between time and speed, which is
Time ∝ 1/Speed
So, let's consider that
to go downstream Rajesh takes 1 unit of time and to go upstream he takes 2 unit
of times, since Rajesh takes twice as long to row up as to row down the
river.
We know that speed of
Boat in still water = (D+U)/2
From above we get
Downstream speed is 2 and upstream speed is 1.
So, (2 + 1)/2 = 3/2
But it is given that
boat's speed or Rajesh's speed in still water is 12 km/h.
∴ we can write 12 * 1/3/2
= 12 * 2/3 = 8.
So the downstream speed
is 8 * 2 = 16
We know that
Downstream = Boat's
speed + Speed of Current
∴ 16
= 12 + Speed of Current
Speed
of Current = 4 km/h.
For more examples visit: Examples with Solutions
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