a kayak travels 15/h in still water and if the current flows at a rate a 3km/h how long will it take for the kayak to travel 30km upstream
Time = 30/(15-3) = 5/2 or 2.5 hours
To find out how long it will take for the kayak to travel 30km upstream, we need to consider the effect of the current.
Let's break down the problem. The kayak's speed in still water is given as 15 km/h. This means that, without any current, the kayak can travel at a speed of 15 km/h.
However, there is a current flowing against the kayak's path. The rate of this current is given as 3 km/h. When the kayak is traveling upstream against the current, its effective speed is reduced by the speed of the current.
To calculate the kayak's effective speed upstream, we subtract the speed of the current from the speed in still water.
Effective speed upstream = Speed in still water - Speed of current
Effective speed upstream = 15 km/h - 3 km/h
Effective speed upstream = 12 km/h
Now, we know that the distance to be traveled upstream is 30 km, and the effective speed upstream is 12 km/h.
To find the time it takes to travel, we can use the formula:
Time = Distance / Speed
Time = 30 km / 12 km/h
Time = 2.5 hours
Therefore, it will take the kayak approximately 2.5 hours to travel 30km upstream.