# Chapter 3 Linear Systems and Matrices - 3.2 Solve Linear Systems Algebraically - 3.2 Exercises - Problem Solving - Page 166: 63

The electrician earned $450$ and the apprentice earned $100.$

#### Work Step by Step

Let $x$ be the number of hours the electrician worked. Then the apprentice worked $x-4$ hours. Then our equation is: $50x+20(x-4)=550\\50x+20x-80=550\\70x=630\\x=9$ Thus the electrician earned $9\cdot50=450$, and the apprentice earned $550-450=100.$

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