19200 all you have to do to figure this out is multiply 100 times 8 since the is 8 halfs in 4 hours.
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Answer:
Step-by-step explanation:

{x | x < 0} and {x | x > 0} NO SOLUTION <em>(look at the picture)</em>
<em>There is no number that is both positive and negative.</em>
{x | x ≤ 0} and {x | x ≥ 0} SOLUTION: the number 0
{x | x ≤ 0} or {x | x ≥ 0} SOLUTION: all real numbers