Question

Anisha can row her boat at a speed of 6 km/hr in still water. If it takes her 2 hour
more to row the boat 22.5 km upstream than to return downstream. The speed
of the stream is (in km/hr)​

Answer 1

Answer:

Q1 Solution:

Let the speed of the stream be x km/h

Speed of boat upstream =(5-x) km/h

speed of boat downstream = (5+x) km/h

Time taken to go upstream =5.25/(5-x).

Time taken to go downstream = 5.25/(5+x).

Time = distance / speed.

from the question we can write

[5.25/(5-x)] -[5.25/(5+x)]=1

5.25(5+x) - 5.25(5-x)=(5+x)(5-x)

10.5x=25-x²

x²+10.5x-25=0

(x-2)(x+12.5)=0

∴ x=2 and x= -12.5

(discarding the negative value)

x=2 km/h is the speed of the stream.

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Q2 solution:

Let original duration of tour = x days.

Total expenses = Rs 360

Duration of tour extended = (x+4) days.

extended tour expenses per day =360/(x+4)

expenses per day =360/x

Given that expenses per day is cut by rs 3

((360/x)-(360/(x+4))=3

360(x+4)-360 x=3(x(x+4))

3x²+12x-1440=0

3(x+24)(x-20)=0

x=-24 and x=20

Discarding the negative value

 we get x=20.

So the original duration of the tour was 20 days.

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Answer:

Step-by-step explanation:

Speed of boat in still water = 5 km/h

Let speed of stream be 'x' km/h.

Speed of boat in upstream = (5 - x) km/h

Speed of boat in downstream = (5 + x) km/h

Distance travelled by boat in upstream = Distance travelled by boat in downstream = 5.25 km

ATQ:-

5.25(1/5-x - 1/5+x) = 1

=> 5.25 ( 2x/25 - x2) = 1

=> 10.5x = 25 - x2

=> x2 +10.5x - 25 = 0

=> (x+12.5)(x-2) = 0

=> x = 2 or x = -12.5

x can't be -12.5 as speed can't be negative

Therefore, Speed of stream is 2 km/h.

Answer 2

Answer:

Let the speed of the stream be x km/h

Speed of boat upstream =(5-x) km/h

speed of boat downstream = (5+x) km/h

Distance travelled by boat in upstream=Distance travelled by boat in downstream=5.25 Km.

ATQ:-

→ 5.25(1/(5-x)-1/(5+x)=1.

→ 5.25 (2x/(25-x^2)=1.

→ 10.5x=25-x^2=0.

→ (x^2+10.5x-25=0.

→ (x+12.5)(x-2)=0.

→ x=2 Or x= -12.5

Speed can't be negative. So speed = 2 km/h