Ranking results based on ELO system

Hi all,

I'm interested in an idea where I have a range of results (out of 100) and would like to output an ELO rating (1000-2800) based on their results.

Is it possible to convert a result out of 100 into a ranking system such as ELO?

If not, what is a good system where I have multiple results and would like to identify which person is top performing (say top 10%).

I wans't able to upload excel file. I've attached a simple image.

Capture.JPG

I'm thinking of something like this, if the tests was a hard and the result was high that translates to high elo. Where as if the test was easy and the result was high, it would translate to a low elo.

Ideally it needs to take into account of all those results (with varying difficulty level factored in).

I was thinking of assigning each result with its own ELO rating and that would act as how difficult it was. In terms of formulas, i was thinking of using the follwing in the image.Attachment 756358