This is the sample space of 52 cards:

AH 2H 3H 4H 5H 6H 7H 8H 9H 10H JH QH KH 
AD 2D 3D 4D 5D 6D 7D 8D 9D 10D JD QD KD
AS 2S 3S 4S 5S 6S 7S 8S 9S 10S JS QS KS
AC 2C 3C 4C 5C 6C 7C 8C 9C 10C JC QC KC

I will now color the successful cards red:

AH 2H 3H 4H 5H 6H 7H 8H 9H 10H JH QH KH 
AD 2D 3D 4D 5D 6D 7D 8D 9D 10D JD QD KD
AS 2S 3S 4S 5S 6S 7S 8S 9S 10S JS QS KS
AC 2C 3C 4C 5C 6C 7C 8C 9C 10C JC QC KC

So you see that there are only 8 ways to succeed in getting a king 
or queen, and there are 52 ways total to succeed or fail. So that's
8 successful ways out of 52 possible ways, so to get the probability 
you put 8 over 52, getting the fraction  which reduces to .  

Edwin