In a survey of 120 families, 76 families have a television, 45 have a computer and 28 have both. How many families have a television but not a computer?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 48
The 76 families that have a television include the 28 that have a computer as well. Those with a television but not a computer are what is left after taking these 28 away.
Television only \(=76-28=48\)
(Computer only \(=45-28=17\); neither \(=120-(48+28+17)=27\))
Checking the other options
Option (2): 17 — Incorrect. This is the number with a computer but not a television.
Option (3): 27 — Incorrect. This is the number of families with neither of the two.
Option (4): 76 — Incorrect. This is the number of all television owners, including the 28 who also have a computer.