Answer:

The third reading must be between 6.3 and 8.1 inclusive.
Step-by-step explanation:
To find the average of three numbers, add the three numbers and divide by 3.
Let the third reading = p.
The average of the three readings is

This average must be between 7.2 and 7.8 inclusive. "Inclusive" means that the values 7.2 and 7.8 are allowed. That means the average must be greater than or equal to 7.2 and less than or equal to 7.8. We can write this as the following inequality.

Simplify the numerator.

Multiply the three sides by 3.

Subtract 15.3 from the three sides.

Answer: The third reading must be between 6.3 and 8.1 inclusive.
HI there i know this is way later than you needed it but I though i would give you the correct answer which is B x=±√15/3 i also have proof from an old test that my answer is right.
Answer is: Bella saves more per chore than Sweet T.
Bella began with 11 dollars and Sweet began with 10 dollars. Bella also earns 1.5 dollars more compared to Sweet T. This means that overall, Bella earns more and has more money compared to Sweet T.
Is there another part to this question? What should we answer?