Somebody can help me with those questions All please

1] Temperature over the course of an afternoon
This is because graph of typical step function are always plotted in such a way that there is an independent variable which defines the outcome of a dependent one, temperature is not dependent on any factor, it is a random occurrence.
Answer: d] Temperature over the course of an afternoon

2] Discontinuous points are those points which are not defined. From the graph, the number of discontinuous points are 4.
Answer: 1] 4

3]The rate of increase of the function between 10 and 15?
rate of change=(change in y-values)/(change in x-axis)
using point (10,0) and (15,0)
=(0-0)/(15-10)=(0/15)=0
Answer [2] 0

4] a] Stacey Johnson earned $50,825 in 2005, how much was her income tax?
Amount of $50825 is between the income range of $50800 and 50, 900. Thus the tax deductions will be: $3570

b] What was the approximate tax rate paid?
rate=(tax paid)/(income earned)
rate=3570/50825
      =0.07024
c] Her brother, Thomas paid $3510 in taxes, Express his income as an inequality.
The range of tax of $3510 is:
50,400≤x≤50,500