The members of a group travelling to Venice were offered by their travel agency 4 additional disjoint options of their choice.
Knowing that each option was selected by 80% of the members, what minimal percentage p choose ALL THE 4 OPTIONS?
The minimum p is achieved when as many members as possible choose 3 out of 4 options.
If 20% choose all but option 1,
and a different 20% choose all but option 2,
and a different 20% choose all but option 3,
and a different 20% choose all but option 4,
then that leaves 20% of the members that chose all options.
The minimum p is therefore 20%. Final answer.
I want it all (spoiler)
