Texas Instruments TI-83 Plus Manual Book page 141

Chapter 5: Linear Systems
Section 2: Using Algebra
Extra Practice: Using Substitution or Elimination
1. Cathy found a part-time job for the summer. Each week, when she works up to 10 hours,
she earns a regular hourly wage. If she works more than 10 hours each week, she earns
more money per hour for the overtime hours. She worked 14.5 hours during the first week.
Her paycheck, before taxes and deductions, was $93.75. The second week, she worked 12
hours and her paycheck, before taxes and deductions, was $75.00. Cathy's boss had told her
what her hourly and overtime rates were, but Cathy was so excited to get the job that she
couldn't remember what she was told.
• Write a system of equations for Cathy's hourly and overtime pay rates. Clearly define the
variables and their meanings.
•
Solve the system of equations using substitution. Show your work and explain the steps
you used to solve the system of equations. Show the check of your solution.
• Write a sentence explaining Cathy's pay rate. ___________________________________
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Topics in Algebra 1
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© 2001, 2002 Texas Instruments Student Worksheet 5-18