D, volume = widthxheightxlength
The given sequence is:

a(2)=1
a(3)=3
a(4)=9
We are to find the average rate of change between n=3 and n=4 for the given function.
Average rate of change =

So the average rate of change for the given function from n = 3 to n = 4 is 6
7 because the 3 is the coefficient and the x is the variable. The + is the operator so that leaves you the 7
Equation for Kelli's earning = 20x + 100
Equation for Karl's earning = 25x + 50
Now, 20x +100 = 25x +50
25x-20x = 100-50
5x = 50
x = 10
So, your answer is 10 hours.
Hope this helps!
Step-by-step explanation:
suppose,x=1,2 .so y=1+4=5,2+4=6...eq..(I)
and y=2×1-8=-6,y=2*×2-8=-4
now plot in graph where they intercept with each other i.e x and y
I could plot but it's difficult here..and remember u can suppose any point as x for y