Dylan uses 8 ice cubes in his glass plus 2 x as many for the pitcher of lemonade, 8 x 2 = 16 ice cubes.
Those 16 ice cubes + the 8 before means that the ice cube trays originally held 16 + 8 ice cubes = <<16+8=24>>24 ice cubes.
Each ice cube tray holds 12 ice cubes, 24 ice cubes / 12 spaces in the trays = <<24/12=2>>2 total ice cube trays.
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