My dog paddle 11 miles downstream in one hour, but it took him one hour to paddle of 3 miles upstream. How fast could the dog paddle in still water

Answer 1

distance = speed times time

time = distance/speed

t = d/s

1 hour = 11/(s+c) = 3/(s-c) s=speed in still water, c= speed of the current

s+c = 11

s-c = 3 add to eliminate one variable

2s =14

s = 7 mph in still water

c =4 mph for the river current speed

the dog goes 11 mph downstream and 3 mph upstream