The museum has 2 * 12 + 1 = <<2*12+1=25>>25 paintings displayed in the painting wings.
There are 4 times as many artifacts displayed, so there are 25 * 4 = <<25*4=100>>100 artifacts.
There are 8 wings and 3 are painting wings, so there are 8 - 3 = <<8-3=5>>5 artifact wings.
Each artifact wing has 100 / 5 = <<100/5=20>>20 artifacts in it.
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