Question

ritu can row downstream 20km in 2 hours and up stream 4 km in 2 hrs find her speed of rowing in still water and in stream water

Answer 1

Ritu can row downstream 20 km in 2 hours
so, Speed of downstream,
Sd = 20/2 = 10km/h

Ritu can row upstream 4 km in 2 hrs
so, Speed of upstream,
Su = 4/2 = 2km/h

Speed of the boat in still water = 1/2( speed of downstream - speed of upstream) = 1/2( 10+2) = 1/2(12) = 6km / hr

Speed of the stream = 1/2( speed of downstream - speed of upstream) = 1/2(10-2) = 1/2(8) = 4km/hr