Since Daisy is 6 inches taller than Reese, she must be 60 inches + 8 inches = 68 inches tall.
Parker is 4 inches shorter than Daisy, making her 68 inches – 4 inches = <<68-4=64>>64 inches.
The average height of the three of them is (60 inches + 68 inches + 64 inches) / 3 = <<(60+68+64)/3=64>>64 inches.
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