SOLUTION
From the question, we will apply the Zscore formula
[tex]\begin{gathered} Z=\frac{x-\mu}{\sigma} \\ x=20,\mu=30,\sigma=5 \end{gathered}[/tex]Applying, we have
[tex]\begin{gathered} Z=\frac{20-30}{5} \\ Z=-\frac{10}{5} \\ Z=-2 \end{gathered}[/tex]Using the Zscore calculator, we have that
P(x<20) = 0.02275
Hence the answer is 0.023