Need help figuring out odds

[Wisco Kidd]

So I just started reading Winning Low Limit Holdem and one of the odds he puts out there is if you hold AK in the pocket you have a 2.1:1 of hitting either an A or K on the flop. Math is not my strong suit, so can someone please expain how this is the case. I understand that, there are 3 Aces left and 3 Kings left out of 50 possible cards. So the odds on the first card to hit the flop is 44:6 (is that much correct?) and the second card on the flop will be 43:6 and the third card is 42:6. How do those work out to be 2.1:1? Thanks for any help you can offer.