00:01
Hi, here in this given problem, suppose speed of the boat in still water, that is vb, and speed of water current, suppose this is vw, then upstream speed, up stream, speed, upstream means when the boat is moving in a direction opposite to the direction of water current.
00:50
So, upstream speed of the boat will be given by vb minus vw and down stream means when the boat is moving with the water current, then down stream speed will be given by vb plus vw.
01:12
Now using the expression for the speed, speed is equal to distance upon time.
01:19
So for the upstream motion, 30 kilometers are covered in 5 hours.
01:27
So the total upstream speed is actually 6 km per hour.
01:34
And in downstream motion, vb plus vw, and it is given that 24 kilometers are covered in 3 hours.
01:42
So here it comes out to be equal to 8 km per hour...