You are dealt 4 cards at random from a standard deck of 52 (without replacement). A standard deck of 52 contains 13 different denominations of cards (ace, 2, 3, ..., 10, jack, queen, king), each in four different suits (hearts, spades, diamonds and clubs).There are 2 events,

A = dealt a hand where all 4 cards are different suits

B = dealt a hand with at least two cards of the same denomination

So that is the probability of being dealt either A or B (So whats P(A U B)?)

Full explanation and work needed