"Pluto was the first dwarf planet to be discovered" is the one statement among the following choices given in the question that is true <span>about dwarf planets. The correct option among all the options that are given in the question is the first option or option "a". Pluto was classified as a planet at first but in the year 1930 it was classified as a dwarf planet.</span>
Now I can actually edit my answer directly: I'm fairly sure I've got this wrong, and my mind has gone blank for how to do it, if someone could delete this that would be great and I'll think about it and see if I can figure it out!
Given parameters:
Displacement = 8km
Velocity = 3.8km/h
Unknown:
time = ?
Solution:
Velocity is displacement divided by time.
Velocity = 
Displacement = velocity x time
Input the parameters:
8 = 3.8 x time
Time = 
= 2.1s
The time taken is 2.1s
