If the splash is hear 4.23 seconds after a stone is dropped into a well, 78.4 metres deep, find the velocity of sound in air.

Explanation

To solve the problem, we need to find the velocity of sound in air given that a stone is dropped into a well and the splash is heard 4.23 seconds later. The depth of the well is 78.4 meters.

### Step-by-step Solution:

1. **Understanding the Problem**:
- The total time taken from dropping the stone to hearing the splash is 4.23 seconds.
- This total time consists of two parts: the time taken for the stone to fall (T1) and the time taken for the sound to travel back up the well (T2).

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