FLYING T-SHIRTS ANSWER KEY
1. Consider the function described in the table below.
Input
-7
-5
-3
Output
-28
-20
-12
2
8
5
20
Describe what this function “machine” is doing.
This function machine takes numbers and multiplies them by -4.
Express this function using function notation. f(x) = _____________________
Answers may vary. For example f(x) = -4x.
2. Jacob has started a new job working for his neighbor Paul. Paul said that his weekly pay would
be a function of the hours he worked. What does this mean?
The amount of pay he receives depends on the number of hours he works.
Complete a table that might describe Jacobs’s weekly pay as a function of the hours he worked.
Be sure to describe the input and output variables. Answers will vary.
Hours
worked
Weekly Pay
(in dollars)
2
5
20
15
0
8
24
60
120
180
0
96
What things did your group have to decide before you completed the table?
We decided to pay Jacob $12.00 per hour
3. Rocko needs to lose weight to wrestle in the 104 pound weight class. He currently weighs 135
pounds and estimates that he can lose an additional 2.5 pounds per week. Express this function
using a table and function notation.
F(x) = 135 – 2.5x
Week #
Weight in
lbs.
0
1
2
3
4
5
135
132.5
130
127.5
125
122.5
When will he make weight? Use mathematics to justify your answer.
It will take him 13 weeks to make weight. F(12) = 105 lbs and F(13) = 102.5 lbs.
4.
Describe the function f (t)  20t  50 a table and a story that this function is describing.
Describe what is represented by the domain and what is represented by the range. Answers will
vary
The signup fee for the Unlimited Bowling Club is $50 plus a monthly fee
of $20.
5. Marcus is launching t-shirts into a crowd of people from the top of a 30ft tower. The height of
the t-shirts above the tower as a function of time can be described by the function below.
h(t)  16t 2  50t  30 .
Use the function to determine the height of the t-shirt at each given time in seconds. Write a
complete sentence to interpret your solution in terms of the problem situation.
a. h(3) = 36
b. h(0)= 30
c. h(5)= -120
d. What is special about the value of h(0)?
It is the height of the tower (30 ft.)
e. Look at the height for h(5). Since the tower is 30 feet tall, what does this tell you about
what has happened to the t-shirt?
-120 feet means the object has hit the ground.