A boat covers a certain distance downstream in 3 hrs and the same distance upstream in 5 hrs. If the speed of the boat in still water is 8km/hour, find the speed of the stream. help me please I am struggling to solve this question​

The stream's speed is 2 km/hr. We don't need to know the distance.

Step-by-step explanation:

Let the stream's speed = x

rate * time = d

The distance is the same going upstream as it is coming back down stream.

d_upstream = d_downsteam

(8 + stream)*3 = (8 - stream)*5

(8 + x)*3 = (8 - x)*5                    Remove the brackets

24 + 3x = 40 - 5x                      Subtract 24 from both sides.

3x = 40 - 24 - 5x

3x = 16 - 5x                               Add 5x to both sides

3x + 5x = 16

8x = 16                                      Divide by 8

x = 16/8

x = 2

Step-by-step explanation:

4a = 3b

4a = a+b+c

c = 3a-b, so

4(3a-b) = 3b

12a-4b = 3b

12a = 7b

subtracting,

8a = 4b

or

4a = 2b

But, 4a = 3b, so

2b = 3b

b=0