Question 199340
Let  x  =  velocity  in  still  water
.
Distance  =  Velocity  *  Time
.
D1 = (x+6) 5 = 5x +30
.
D2 = (x-6) 10 = 10x -60
.
but  D1 = D2
.
5x +30 = 10x -60
.
90 = 5x
.
18 = x
.
checking
.
(18 +6) * 5 = (18-6) 10
.
120 =120,,,,ok