To solve this question we will use the following property of ratios:
[tex]ab\colon ac=b\colon c\text{.}[/tex]Now, notice that:
[tex]\begin{gathered} 36=4\cdot9, \\ 40=4\cdot10. \end{gathered}[/tex]Therefore:
[tex]36\colon40=4\cdot9\colon4\cdot10.[/tex]Using the above property of ratios we get:
[tex]4\cdot9\colon4\cdot10=9\colon10.[/tex]Answer: 9 to 10.