How to quantify assessment on JotForm?

How can I quantify an assessment so that it gives me a percentage /pass rate upon completion. 

https://www.jotform.com/build/90932481516560

Please note that you can add "Calculation Value" in your single/multiple choice question along with dropdown field. This will allow you to add value to each of the options you have in your question. You can then add "Form Calculation" widget in form to calculate the score based on the selection value.

You may like to take a look at the following guides which should help you:

Add calculation values: https://www.jotform.com/help/301-How-to-Assign-Calculation-Value  

Perform calculation:  https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget 

Hope this helps.

Do get back to us if you have any questions.