the average speed of butterfly is 20.5 ft/s
[tex] \frac{82}{4} = 20.5[/tex]
the average speed of dragonfly is 25ft/s
[tex] \frac{50}{2} = 25[/tex]
so the difference is
[tex]25 - 20.5 = 4.5[/tex]
the dragonfly can fly faster 4.5 ft more in a second.
good luck
