Question 1115400
In a normal deck of 52 cards what is the probability that {{{cross(the)}}} a card drawn is
a) divisible by 3 
b) a 7 of any suit or a diamond 
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a)  divisible by 3:  those are cards with rank 3, 6, or 9.  Arguably one could include Q as well, it depends on the game.   Many games treat all face cards as "10" but in games like poker, Q is greater than 10.  <br>         

Using 3,6, or 9 only:   P(3,6,or 9) =  12/52 = {{{highlight( 3/13 ) }}}
Using 3,6,9, or Q:   P(3,6,9, or Q) =  16/52 =  {{{highlight( 4/13 ) }}}
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b)  There are four 7's and 13 diamonds:   4/52 + 13/52  = 17/52  
However, the 7 of diamonds has been counted twice, so  the answer is  17/52 - 1/52 = 16/52 =  {{{highlight( 4/13 ) }}}