No Heads TTTT = 4C0 = 1 One Heads HTTT = 4C1 = 4 Two Heads TTHH = 4C2 = 6 Three Heads HHHT = 4C3 = 4 Four Heads HHHH = 4C4 = 1
Total chances = 1 + 4+ 6+4 +1 = 16
One head + 4 head = 4 +1 = 5
Total probability = 5/16
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