Question

The pH scale measures how acidic or basic a substance is. Lemon juice is said to have a pH of less than 4 and greater than 1.5. Model the normal range of pH values of lemon juice, using a compound inequality.
1.5 > x > 4
1.5 < x < 4
1.5 ≤ x ≤ 4
1.5 ≥ x ≥ 4

Answer 1

Let's say x is J because it's Lemon Juice.

It's said that the pH of J is less than 4 so: pH(J) < 4 and pH(J) is greater than 1.5 so: pH(J) > 1.5

Now we can construct:

$1.5 < pH(J) \wedge pH(J) < 4$

Or simply:

$1.5 < pH(J) < 4$

We can also write this with an interval:

$pH(J)\in(1.5, 4)$

Hope this helps.

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