For this case we have the following function:

By definition, the average rate of change is given by:

We evaluate the function for the given values:
For x = 7:

For x = 14:

Then, replacing values we have:
Answer:
the average rate of change from x = 7 to x = 14 is:
a. 23.22
Recall that

There are three cases to consider:
(1) When

, we have

and

, so

(2) When

and

, we get

and

, so

(3) When

, we have

and

, so

So
20% of 100 is 20. divide that by 2 to get 20% of 50. 20/2 is 10. 20% of 50 is 10. There are 10 blue marbles.
Hope it helped :)
Ali
The answer is 9.63 x 10^12