Answer:
Kevin must have used simple random sampling.
Explanation:
We can say that Kevin used simple random sampling. This is because this type of sampling allows elements to be taken from a population in a completely random way, to form a sample. In this case, each element, or individual, as shown in the question above, has the same probability of being selected to compose the sample, since this selection is completely random.
Answer:

Explanation:
From the question we are told that:
Speed of Motor 1 
Speed of Motor 2 
Therefore
Frequency of Motor 1 
Frequency of Motor 2 
Generally the equation for Time Elapsed is mathematically given by

Where



Therefore


Answer:
D) the two spheres remain of equal size.
Explanation:
- Since the body of the sphere is made up of both the same material. Thus the orientation will not affect the expansion. That is solid upon solid and hollow upon the hollow sphere. Hence it can be said that both the sphere expands and is due to the material used for making both of them is the same.
If 3cm represents 30km/h then that means 1cm represents 10km/h. So, a 5cm long vector will represent a velocity of 50km/h