Question

find the solution .a man can swim at 6 km/hour. The speed of a stream is 2 km/hour. How much time will the man take to swim 400m if(a) he is swimming with the stream?(b) he is swimming against the stream?

Answer 1

see is this right first add both of the speed then convert into m/sec then use the formula of distance or speed you will get the answer and for against you subtract (6-2) =4km/h and then convert into 10/9m/s and then the answer is 400÷10/9=360s means 6min

Answer 2

in case a both the speeds are in same direction so we need to add the speeds we get 8 KMPH convert it to m/s it will be 20/9 m/s now time taken is distance/speed =400×9/20=180s , in case 2 it is downstream so we need to subtract the river speed from the man's speed we get 4kmph means 10/9 m/s the time taken is 400×9/10=360s