Answer:
We know that Jennifer ran 10k last weekend.
Now, we have the function:
t = f(k) = 7*k
(notice that this is a linear function)
First, let's define what is the range.
The range is the possible values that the outcome, t, can take.
To see the range, we first must see the domain (the possible values of of the input)
In this case, we know that the minimum value of k is 0 (the time to run 0 kilometers)
t(0) = 7*0 = 0
Here we found the minimum of the range.
Now, the maximum value in the domain is 10 (because she ran 10km, we can not have a value of k larger than 10)
The time is:
t(10) = 7*10 = 70
This will be the maximum of the range.
Then the range can be written as:
R = [0, 70]