Out of 100 members of the billionaires' club "Scrooge McDuck":
93 have a mansion;
90 have a car collection;
81 have a private jet;
75 have a private island;
62 have an art collection
What is the least number of the billionaires who have all five items ?
I do this one base on the concept: to ensure minimum people get too many of them we spread out the goodies.
Thus no billionaire has no item (Neither = 0)
93 have a mansion (M) => 7 dont have mansion => Give these 7 all other four items
90 have a car collection (C) => 90 - 7 = 83 left => 83 will have both M & C => 100 - 83 - 7 = 10 who have M but dont have C
=> we have: 83 have MC; 17 dont have at least 1 M or C => continue to give these 17 all other 3 items
81 have a private jet (J) => 81 - 17 = 64 left => pick 64 from 83MC
=> 64 have all three M,C & J (64MCJ) and (83-64) = 19 have M,C but not J
Then we have 17 + 19 = 36 dont have at least one items (M or C or J) => continue to give these 36 all other 2 items
75 have a private island (I) => 75 - 36 = 39 left => continue to pick 39 from 64MCJ
=> we have 39MCJI (39ppl have all 4 items) and (64 - 39) = 25 billionaires who dont have item I
Thus till now, we have 36+25 = 61 billionaires who dont have at least one above items (M or C or J or I)
=> continue to give these 61 the fifth item
62 have an art collection (A) => 62 - 61 = 1 left
Hence only 1 billionaire must receive all 5 items
p/s: Im sorry for so many words, hope someone have better solution. Please see attached image for easier understanding. Manythanks
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