An engineering technician makes [tex]$25 an hour for the first 40 hours she works during a week and $[/tex]32 an hour for each hour over 40 hours. Which piecewise equation models her total weekly pay [tex]\( y \)[/tex] in dollars as it relates to the number of hours [tex]\( x \)[/tex] that she has worked during the week?

A. [tex]\( y = \begin{cases} 25x & 0 \leq x \leq 40 \\ 32(x-40) + 1000 & x \ \textgreater \ 40 \end{cases} \)[/tex]

B. [tex]\( y = \begin{cases} 25x & 0 \leq x \leq 40 \\ 32x + 1000 & x \ \textgreater \ 40 \end{cases} \)[/tex]

C. [tex]\( y = \begin{cases} 25x & 0 \leq x \leq 40 \\ 32x & x \ \textgreater \ 40 \end{cases} \)[/tex]

D. [tex]\( y = \begin{cases} 25x & 0 \leq x \leq 40 \\ 32(x-40) & x \ \textgreater \ 40 \end{cases} \)[/tex]



Answer :

To determine which piecewise equation models the total weekly pay [tex]\( y \)[/tex] for the number of hours [tex]\( x \)[/tex] that the engineering technician works, we need to consider two cases: when [tex]\( x \)[/tex] is between 0 and 40 hours, and when [tex]\( x \)[/tex] exceeds 40 hours.

1. Case 1: [tex]\( 0 \leq x \leq 40 \)[/tex]
- For any number of hours [tex]\( x \)[/tex] within this range, the technician earns [tex]$25 per hour. - Therefore, the total weekly pay \( y \) can be calculated using the equation: \[ y = 25x \] 2. Case 2: \( x > 40 \) - For the first 40 hours, the technician earns $[/tex]25 per hour, which totals:
[tex]\[ 25 \times 40 = 1000 \text{ dollars} \][/tex]
- For any additional hours beyond the initial 40 hours, she earns $32 per hour. If [tex]\( x \)[/tex] is the total number of hours worked in the week, the additional hours are [tex]\( x - 40 \)[/tex].
- Therefore, for these additional hours, the earnings would be:
[tex]\[ 32 \times (x - 40) \text{ dollars} \][/tex]
- Adding the earnings from the first 40 hours and the additional hours gives the total pay [tex]\( y \)[/tex]:
[tex]\[ y = 1000 + 32(x - 40) \][/tex]

Combining these two cases into a single piecewise-defined function gives us:
[tex]\[ y = \begin{cases} 25x & \text{if } 0 \leq x \leq 40 \\ 32(x - 40) + 1000 & \text{if } x > 40 \end{cases} \][/tex]

Considering the given options:
- Option A: [tex]\( y=\left\{\begin{array}{ll} 25 x & 0 \leq x \leq 40 \\ 32(x-40)+1000 & x>40 \end{array}\right. \)[/tex]

Based on this step-by-step reasoning, the correct answer is Option A.

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