Question

1) The speed of a boat in still water is 8 kms/hr. If the boat can go 15 kms downstream and 22 kms and upstream in 5 hours. Then let us by calculating the speed of the stream. ​

Answer 1

Answer:

Answer:

3 KM/h

Step-by-step explanation:

let X be the speed of the stream

speed of the boat in still water = to 8 km /hr

thus the speed of the boat in upstream =(8-x) km/hr

speed of the boat in downstream =(8+x )km/hr

the time taken by boat to cover 15 km

the time taken by boat to cover 22 km

total time =5hrs (given)

x=3

since speed cannot be negative

Therefore speed of steam is 3km/hr

hope this helps you

Answer 2

Answer:

Given :-

• The speed of a boat in still water is 8 kms/hr. If the boat can go 15 kms downstream and 22 kms and upstream in 5 hours.

To Find :-

• The speed of the stream.

Solution :-

Let the speed of stream = x km/hr.

In down stream, speed of boat = (x + 8)km/hr.

In up stream speed of boad = (8 - x)km/hr.

Time taken to go 15 kms. in downstream = $\dfrac{15}{8 + x}$

Time taken to go 22 kms. in up stream = $\dfrac{22}{8 - x}$

According to the question,

➛ $\dfrac{15}{8 + x} + \dfrac{22}{8 - x} = \dfrac{5}{1}$

➛ $\dfrac{120 - 15x + 176 + 22x}{(8 + x)(8 - x)} = \dfrac{5}{1}$

➛ $\dfrac{7x + 296}{64 - x²} = \dfrac{5}{1}$

➛ 7x + 296 = 320 - 5x²

➛ 5x² + 7x + 296 - 320 = 0

➛ 5x² + 7x - 24 = 0

➛ 5x² + 15x - 8x - 24 = 0

➛ 5x(x + 3) - 8(x + 3)

➛ (x + 3)(5x + 8) = 0

➛ x + 3 = 0 ; 5x + 8 = 0

➡ x = - 3 ; x = $\dfrac{8}{5}$ = $1\dfrac{3}{5}$

Hence, speed of current is not in negetive.

$\therefore$ Speed of stream is $1\dfrac{3}{5}$ km/hr.