Question $4$: Doppler Effect and Beats

Standards: SHM$,$ Oscillations, Waves, and Resonance $(7)$

A student holds a tuning fork oscillating at $f=256Hz$ and walks toward a wall at a constant speed of $v_{\text{s}\text{t}\text{u}\text{d}\text{e}\text{n}\text{t}}=1\mathrm{.}33\frac{m}{s}.$ The speed of sound is $v_{\text{s}\text{o}\text{u}\text{n}\text{d}}=343\frac{m}{s}.$

a$.$ What is the frequency of the echo $f^{\text{'}\text{'}}$ that the student will hear after the sound bounces off the wall? Hint: First find the frequency $f^{\text{'}}$ that bounces off the wall and then treat the wall as the source of the echo.