Sound, stationary wave question?

Question

pls help me out so that i can understand how to solve this. thanks!

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A uniform tube, 60.0cm long, stands vertically with its lower end dipping into water. When the length above water is 14.8cm, and again when it is 48.0 cm, the tube resounds to a vibrating tuning-fork of frequency 512Hz. Find the lowest frequency to which the tube will resound when it is open at both ends.

Answer 1

L=60cm=0.6m

speed of sound=v=340 m/s

The lowest frequency corresponds to the longest wavelength,

which for tube opened at both ends is:

λmax/2=L

λmax=2L=1.2 m

f=v/λ

fmin=v/λmax=v/(2L)=340/1.2=283.33 Hz