Answer
Organ Pipe A has both end open.
Organ Pipe B has one end open.
speed of sound, v = 343 m/s
The fundamental frequency = 270 Hz
wavelength of the pipe when both end open
λ = 2 L
we know,

now,

inserting all the values

L_A = 0.635 m
length of pipe A is equal to 0.635 m
b) since third harmonic of pipe B is equal to second harmonic of pipe A



L_B = 0.476 m
length of pipe B is equal to 0.476 m.