a mortor-boat whose speed is 30km/hr in water goes 30km downstream and comes back in a total time of 4hrs 30 minutes find the speed of the stream.

The speed of the stream is 22.36 km/h.

Step-by-step explanation:

The course of the boat contains two stages of equal length. On the first one he is going downstream, so its resultant speed is "30 + x" km/h, where "x" is the speed of the stream. On the other hand for the second part of the course he is going against the stream, so the resultant speed is " 30 - x" km/h. The time of each course must be:

The sum of these times must be equal to the total time of the course, therefore:

The speed of the stream is 22.36 km/h.

28

step-by-step explanation:

because that's the answer

answer: b

step-by-step explanation: