Question 300674
I think using x and y is counter-intuitive.
r for crew rowing and c for current
d for distance
t for time
rate*time=distance
(r+c)*t=d
(r+c)*2=16
(r-c)*2=8
2r+2c=16
2r-2c=8
add
4r=24
r=6
crew rowing=6
(6+c)*2=16
6+c=8
c=2
current=2
check
(6-2)*2=8
4*2=8
8=8
ok