Question 1145089
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<pre>
(a)  First calculate the number of those workers who own at least one of the items.


     For it, calculate the alternate sum


         560 + 560 + 275 - 350 - 220 - 160 + 150 = 815.


     The rest 830 - 815 = 15 workers do not own any of the three items.    <U>ANSWER</U>



(b)  Only cars and houses   350 - 150 = 200.

     Only cars and boats    160 - 150 =  10.

     Only houses and boats  220 - 150 =  70.


     The subsets of workers counted in the previous 3 lines are DISJOINT.


     Therefore, the number of workers who own only two items is  220 + 10 + 70 = 300.    <U>ANSWER</U>
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For more details and explanations, read the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/misc/Advanced-probs-counting-elements-in-sub-sets-of-a-given-finite-set.lesson>Advanced problems on counting elements in sub-sets of a given finite set</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/misc/Challenging-problems-on-counting-elements-in-subsets-of-a-given-finite-set.lesson>Challenging problems on counting elements in subsets of a given finite set</A> 

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