Question 628117
The 48% that own neither can't be divided and does
not overlap with either of the others, so it's fixed
The others have to add up to 100% - 48% = 52%
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So, the percentage that must own both is
( 21% + 48% ) - 52% = 47%
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And the percentage that own either is
52% - 47% = 5%
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Check:
Does ( either ) + ( both ) + ( neither ) = 100%
( 5% + 47% + 48% = 100%
OK