Find the number of 5-card combinations out of a deck of 52 cards if a least one of the five cards has to be king.
Since there are 52 cards in a deck out of which 4 are king and others are non-kings.
So, the no. of ways are as follows:
1. 1 king and 4 non-king
2. 2 king and 3 non-king
3. 3 king and 2 non-king
4. 4 king and 1 non-king
So , total no. of ways are
= 4C1
48C4 + 4C2
48C3 + 4C3
48C2 + 4C4
48C1
Applying nCr = 
= 778320+103776+4512+48
= 886656 ways.
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