Question 453393
let speed of current be x mph

paddling speed = 2x
...
upstream speed = 2x-x = x mph
downstream speed = 2x+x = 3x
...
distance up down is the same

d= rt.

time upstream = 22 hours
d( upstream) = 22x
..
let time downstream be t
d( down stream) = 3x*t

22x=3x*t
t=22x/3x
t= 7.33 hours
They have to leave 7.33 hours before 4.00 pm to meet on time .