Pipe A, which is 1.20m long and open at both ends, oscillates at its third lowest harmonic frequency. It is filled with air for which the speed of sound is 343m/s. Pipe B, which is closed at one end, oscillates at its second lowest harmonic frequency. This frequency of B happens to match the frequency of A. An x-axis extends along the interior of B, with x=0 at the closed end. (a) How many nodes are along that axis?