Question

if eight out of every thirteen trick or treaters that came to your last halloween were dressed as knights, what proportion of tick or treaters were not dressed as knights?

Answer 1

The proportion of knights was 8 : 13, so, to calculate the proportion of not knights, we can start by noticing that the proportion of knights plus the proportion of not knights is everyone, so 1.

We also can notice that 1 can be rewritten as:

`1=(1)/(1)=(13)/(13)`

So, if "p" is the proportion of not knights, then:

`\begin{gathered} (8)/(13)+p=(13)/(13) \\ p=(13)/(13)-(8)/(13) \\ p=(13-8)/(13) \\ p=(5)/(13) \end{gathered}`

That is, the proportion of trick or treaters that were not dresses as knights is 5 : 13.