Answer:
The speed of a boat in still water is 6 miles per hour.
Step-by-step explanation:
t = [tex]\frac{20}{s-2}[/tex] (upstream)
t = [tex]\frac{40}{s+2}[/tex] (downstream)
[tex]\frac{20}{s-2}[/tex] = [tex]\frac{40}{s+2}[/tex]
40 ( s - 2 ) = 20 ( s + 2 )
40s - 80 = 20s + 40
20s = 120
s = 6 mi / h
The speed of a boat in still water is 6 miles per hour.
