arithmetic - a boat running upstream takes 5 hours to cover a certain distance while it takes 2 hours to cover the same distance running downstream what is the ratio between the speed of the boat and speed of the water current respectively - skillgun

Let the man's rate upstream be x kmph and that downstream be y kmph.
Then, distance covered upstream in 5 hours = distance covered downstream in 2 hours
=> x*5 = y*2
=> y = 5x/2
.'. Required ratio = (y+x)/2 : (y - x)/2
=> (5x/2 +x)/2 : (5x/2 - x)/2 => 7 : 3