First, you have to convert the mixed number into a fraction, as follows:
[tex]20\frac{3}{16}=\frac{20\cdot16+3}{16}=\frac{323}{16}[/tex]Now, you have to compute 323/16 divide by 2.
[tex]\frac{323}{16}\cdot\frac{1}{2}=\frac{323\cdot1}{16\cdot2}=\frac{323}{32}[/tex]Half of 20 3/16 is 323/32