The <em>correct answer</em> is:
|w-20| ≤ 0.12.
Explanation:
We first find the average of the two ends of the inequality:
(19.88+20.12)/2 = 40/2 = 20
This will be the number subtracted from w in the inequality.
Now we find the difference between this value and the ends:
20-19.88 = 0.12
20.12 - 20 = 0.12
This will be what our absolute value inequality ends with; the "answer" part, so to speak.
Since this inequality is written in compact form, it must be an "and" inequality; this means the absolute value inequality must be a "less than or equal to."
This gives us
|w-20| ≤ 0.12
