Joseph has 100 * 0.80 = <<100*0.80=80>>80 less boxes than Stan.
Joseph has a total of 100 - 80 = <<100-80=20>>20 boxes.
Jules has 20 + 5 = <<20+5=25>>25 boxes.
John has 25 * 0.20 = <<25*0.20=5>>5 more boxes than Jules.
John has a total of 25 + 5 = <<25+5=30>>30 boxes
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