Current Attempt in Progress

In the figure, S is a small loudspeaker driven by an audio oscillator and amplifier, adjustable in frequency from $900$ to $3000$ Hz only. Tube $D$ is a piece of cylindrical sheet$-$metal pipe $53\mathrm{.}4$ cm long and open at both ends. $($a$)$ If the speed of sound in air is $344\frac{m}{s}$ at the existing temperature, at how many frequencies will a resonance occur in the pipe when the frequency emitted by the speaker is varied from $900$ Hz to $3000$ Hz $?($b$)$ What is the lowest resonant frequency in the given interval?

$($a$)$ Number

Units

$($b$)$ Number $$ Units