In an office, every person likes juice or coffee or both. 80% of the people like juice and 55% like coffee. What percentage of the people like only coffee?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 20%
Everyone likes at least one drink, so the two groups together make up 100%. The amount by which 80% + 55% goes over 100% is the group counted twice, those who like both.
Both \(=80\%+55\%-100\%=35\%\)
Only coffee \(=55\%-35\%=20\%\)
(Only juice \(=80\%-35\%=45\%\); and \(45\%+35\%+20\%=100\%\))
20% of the people like only coffee.
Why the other options are incorrect
Option (1) 35% — Incorrect. This is the share who like both drinks.
Option (2) 55% — Incorrect. This is everyone who likes coffee, including those who also like juice.
Option (4) 30% — Incorrect. It does not come from the overlap of 35%; only coffee is \(55\%-35\%=20\%\).