= Solution
\b[Source notation assumption:] the second printed $V_{p3}=3000\ \mathrm{m\,s^{-1}}$ is interpreted as $V_{s3}=3000\ \mathrm{m\,s^{-1}}$. Otherwise the S-wave velocity in salt is not supplied, and this part and the salt S-wave calculations below would have no numerical answer. Retain the printed <densities>, including the unusually low salt value, rather than silently replacing them with typical rock properties.
With that interpretation, <Snell law for elastic waves> gives
$$
\sin t_S=\frac{3000}{2000}\sin20^\circ,\qquad \boxed{t_S=30.87^\circ}.
$$
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