Question

Sorry it’s messy, but if someone could help with a Step by Step

Answer 1

Answer:

  a) 490

  b) 240

Step-by-step explanation:

b) It is convenient to answer part B first.

The number owning only a fax will be the number owning a fax less the number that own both a fax and a copier:

  420 -180 = 240 . . . . number owning only a fax

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a) The number owning one or the other will be the number owing a copier (which includes those owning both) plus the number owning only a fax:

  250 +240 = 490 . . . . number owning either

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If you want to work part A first, then you need to use the relation ...

  n(A∪B) = n(A) +n(B) -n(A∩B)