The water acidity in a pool is considered normal when the average `pH` reading of three daily measurements is between `7.2` and `7.8`. If the first two pH reading are `7.48` and `7.85`, find the range of `pH` value for  the third reading that will result in the acidity level being normal.

Explanation

To solve the problem, we need to find the range of the third pH reading (let's call it \( R_3 \)) such that the average of the three readings remains between 7.2 and 7.8.

### Step-by-Step Solution:

1. **Understanding the Average Condition**:
The average of three readings \( R_1, R_2, \) and \( R_3 \) should be between 7.2 and 7.8. This can be expressed mathematically as:
\[
7.2 < \frac{R_1 + R_2 + R_3}{3} < 7.8
...