algebra
posted by ashley .
a tugboat goes 160 miles upstream in 20 hours. The return trip downstream takes 5 hours. Find the speed of the tugboat without a current and the speed of the current.

if tugboats speed is s, and current is c,
since the distances are the same, and
distance = speed * time,
(sc)*20 = (s+c)*5 = 160
20s  20c = 160
5s + 5c = 160
or,
20s+20c = 640
40s = 800
s = 20
c = 12
check:
160/32 = 5
160/8 = 20