Question 977014
Imagine the deck cards arranged organized from A to K in one direction and each suit orthogally to the A to K arrangement.  You can make a count of all the cards which are 7 or diamonds.  The deck has FOUR 7's, THIRTEEN diamonds, and this is {{{4+13-1}}}.  The reason for MINUS ONE is that one of the cards is both a 7 and a diamond; so this is subtracted in order to not count it twice. 


Sixteen cards of the deck are 7's or diamonds.


NOW shuffle the 52-card deck.  Shuffle it well.


Chance of pulling 7 or diamond is  {{{16/52}}}.
This is {{{4/13=0.3077}}}...