Arowing team rowed 60 miles while going with the current in the same amount of time as it took to row 10 miles going against the current. the ratio of the current was 5 miles per hour. find the rate of the rowing team in still water.

The first thing we must do for this case is to define variables:
 x = rate of the rowing team in still water
 x + 5 = rate going with the current
 x-5 = rate going against the currrent
 Then, by definition we have:
 d = v * t
 Where
 d: distance
 v: speed
 t: time
 Clearing the time we have:
 t = d / v
 travel time is equal for downstream and upstream:
 60 / (x + 5) = 10 / (x-5)
 We clear x:
 60 (x-5) = 10 (x + 5)
 60x-300 = 10x + 50
 50x = 350
 x = 350/50
 x = 7
 
 The rate of the rowing team in still water is:
 x = 7 mph