The mailman has 48 pieces of junk mail / 8 houses = <<48/8=6>>6 pieces per house.
The houses with white mailboxes get 2 * 6 pieces = <<2*6=12>>12 pieces of junk mail.
The houses with red mailboxes get 3 * 6 pieces = <<3*6=18>>18 pieces of junk mail.
The houses with red and white mailboxes will get a total of 12 + 18 = <<12+18=30>>30 pieces of junk mail.
30/5 = <<30/5=6>>6 pieces of junk mail each
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