How many dollars does the person earn for that long day? $200

PARTICIPATION ACTIVITY
Piecewise linear function: Day’s earnings considering overtime pay.
Consider the example above.
1) Looking at the graph above, how much does a person earn for a day if the person worked 9 hours?
$80
$95
$100
2) No one line represents the function. To graph, the first piece’s line is:
0-8 hours: y = 10x
The second piece’s line starts at the first piece’s end, meaning x is 8 and y is 80. What is that line’s slope?
10
15
3) Drawing a line with slope 15, starting at x of 8 and y of 80, can be done by drawing a second point, obtained by going 1 unit to the right and up by how many units?

1
15
95
4) No one equation can represent the piecewise linear function. Instead, the function is described like this:
0-8 hours: y = 10x
8+ hours: y = 80 + 15(x – ?)

1
8
5) For more than 8 hours worked, the total earnings are y = 80 + 15(x – 8). A person works a long 20 hour day. How many dollars does the person earn for that long day?
$200
$260
$380
6) Suppose the company above pays double-time  for above 12 hours. The equations are then:
0-8 hours: y = 10x
8-12 hours: y = 80 + 15(x – 8)
12+ hours: y = ___ + 20(x – 12)
80
140
155
Feedback?
Overtime: Use and abuse