Ruby sorting multiple values
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I got a little problem trying to sort the given of prices and products.

    `arr = [[6,"iPhone"],[4,"Android"],[5,"iPhone"],[3,"Xbox"],[9,"Android"],[8,"Xbox"]]`

But i need to sort it by product and then by price. I make the next common to do it:

    arr.sort_by! {|x| [x[1],x[0]]}.reverse
     => [[6, "iPhone"], [5, "iPhone"], [8, "Xbox"], [3, "Xbox"], [9, "Android"], [4, "Android"]] 

But i need again to sort it now by the block of products to get the most expensive one block first and so on. The result that I'm looking for its like:

`arr = [[9,"Android"],[4,"Android"],[8,"Xbox"],[3,"Xbox"],[6,"iPhone"],[5,"iPhone"]]`

Any help will be appreciated! 