Don't look now, but the question GIVES you the formula to use, and it GIVES you the numbers to plug into the formula.
The formula to use to find the distance covered by the sound is
<em>Speed = (distance) / (time)</em>
They also give you:
speed = 330 m/s
time = 0.40 second
Stuff the numbers into the formula:
330 m/s = (Distance) / (0.40 second)
Multiply each side by (0.40 second), and you get:
(330 m/s) / (0.4 second) = Distance
<em>825 meters = Distance</em>
