Answer:
A)
[tex]1.5\leq x\leq5[/tex]
B) Yes, he has to add more chlorine.
Step-by-step explanation:
What is being said, in other words, is that the absolute difference between the chlorine levels of a sample x and 3.25 ppm has to be, at most, 1.75 ppm.
This situation can be described by the absolute value inequality:
[tex]\lvert{x-3.25}\rvert\leq1.75[/tex]
We can solve this inequality as following:
[tex]\begin{gathered} \lvert x-3.25\rvert\leq1.75 \\ \rightarrow-1.75\leq x-3.25\leq1.75 \\ \\ \Rightarrow1.5\leq x\leq5 \end{gathered}[/tex]
Now, notice that the sample exctracted by the lifeguard is below this interval. Therefore, we has to add more chlorine.
