How long are these organ pipes?

Question

Organ pipe A, with both ends open, had a fundamental frequency of 300 Hz. The third harmonic of organ pipe B, with one end open, has the same frequency as the second harmonic of pipe A.

How long are (a) pipe A and (b) pipe B?

Explain your work. Thanks! :)

Answer 1

A both-ends-open pipe of length L resonates at a wavelength λ = 4L. λ = C/f. Thus L(A) = C/(4f) = 340/1200 m.
The 2nd harmonic of pipe A = 600 Hz. This is the 3rd harmonic of 200 Hz, so 200 Hz is the fundamental frequency of pipe B. A one-end-open pipe of length L resonates at λ = 2L. Thus L(B) = C/(2f) = 340/400 m.

Answer 2

A And B Pipe