The time taken to complete chemistry assignment is, t = 1/2 hours.
The time taken to complete English assignment is, t' = 4/5 hours.
Therefore, the difference is time is,
[tex]\frac{4}{5}-\frac{1}{2}=\frac{8-5}{10}=\frac{3}{10}\text{ hours}[/tex]Thus, Dan spent 3/10 more hours on his english assignment.