javascript, getting a random number result in each singular array

I'm not sure how to word the question and i'm still quite new at javascript. So I've got a random quote generator that has each quote result as an array. I'd like to add in two items in the array which I've got so far but having one result be a random number generated eg "2 quote" but having 2 be randomised each time. The end result is for a browser based text game. So it could be "2 zombies attack" or "7 zombies attack." The code I have so far is:

var quotes = [
[x, 'Zombies attack!'],
[x, 'other creatures attack'],
['next line'],
]  


   function newQuote() {
var randomNumber = Math.floor(Math.random() * (quotes.length));
document.getElementById('quote').innerHTML = quotes[randomNumber];  
}

Ideally need x(or i however it's going to work) to be the result of a random number between a set range, each differently each array.

Thank you