Get index of parent array in handlebars

I have data which is an array of questions, and inside each question is an array of optional answers. What I'm looking to do is to get the index of the question and the answer for each answer.

So I have handlebars loop through the questions then loop through the answers of each one. Here is that:

  {{#questions}}
  <ul>
    <li><strong>{{question}}</strong><br>
    {{#each answers}}
      {{@index}}={{this}},
    {{/each}}</li>
  </ul>
  {{/questions}} 

Here is the data that get's put in:

    data = {
        "questions" : [
            {
                "question":"Favorite Color",
                "answers" : ["red","blue","green"]
            },
            {
                "question":"Favorite food",
                "answers" : ["pizza","pasta","cats"]
            }
        ]
    }

So if I want the index of the answer, I can write @index, but if its an array inside an array, it doesn't work. You can supposedly write ../ to get variables from the parent, but array does not like that.

{{../@index}}-{{@index}}={{this}}

This should give me questionIndex-answerIndex=answer.

But I get an error, something like this:

/home/ubuntu/workspace/views/survey/index.hbs: Parse error on line 16: ... {{../@index}} {{this}}

Error: /home/ubuntu/workspace/views/survey/index.hbs: Parse error on line 16: ... {{../@index}} {{this}}

Here is an example showing it not working: https://codepen.io/samkeddy/pen/oeMeeO (if you take out {{../@index}} it will work.