Salmon hatch in freshwater streams and then migrate 70 miles downstream to the ocean in 8 hours. After reaching spawning age, they return upstream to fresh water to spawn and usually die soon after. If the salmon travel 58 miles in 8 hours during the upstream trip, find the rate of the salmons’ swimming in still water and the rate of the current?

Answer 1

if the salmon's speed is s, and the current's speed is c, then
since distance = speed * time,
(s+c)*8 = 70
(s-c)*8 = 58
now solve as usual