Jake had to attend his sister's junior high band concert. He was not thrilled with the prospect and really did not pay much attention until his sister and another girl played a flute duet of "Mary Had a Little Lamb." He had heard both parts many times at home when they were practicing and knew the notes they were supposed to be playing were high-pitched notes. Now he could hear what sounded like a third flute playing the same tune at least an octave lower. He looked around but could not find a third flute player. What caused the ghostly notes to sound?
Explain YOUR answer! Thanks in advance!