Question 892538
a canoeist can paddle 2 miles up the pasig river in the same time he can paddle 6 miles downstream.
 the speed of the current is 2 mph. what is his speed in still water ?
:
let s = his speed in still water
then
(s+2) = his effective speed downstream
and
(s-2) = his effective speed upstream
:
Write a time equation, time = dist/speed
{{{6/((s+2))}}} = {{{2/((s-2))}}}
cross multiply
6(s-2) = 2(s+2)
6s - 12 = 2s + 4
6s - 2s = 4 + 12
 4s = 16
s = 16/4
s = 4 mph speed in still water
:
:
Check this find the time each way, using the effective  speeds
6/6 = 1 hr
2/2 = 1 hr