Answer:
True, overtone occurs when two or more sounds are produced at the same time.
By definition, we have that the work done is given by:

Where,
F: force in the direction of displacement
d: displaced distance
Substituting values we have:

Then, the power is given by:

Where,
t: time
Substituting values we have:


Answer:
The work done on the box is 100 Nm, and the power is 20 Nm/s.
I believe it would be x because you are trying to find the width of the wave but i could be wrong