Determine the ratio of the number of students who play Football to the number of students who play Basketball in a survey of 120 students from the following table: Category | Number Play Football and Basketball | 25 Play Football but not Basketball | 45 Play Basketball but not Football | 35 Play neither sport | 15

- (a)6:7
- (b)7:5
- (c)7:6
- (d)5:7
Answer
Why
Correct — C. Each sport's total must include the students who play both.
Football = both + football only = 25 + 45 = 70
Basketball = both + basketball only = 25 + 35 = 60
Football : Basketball = 70 : 60
Divide by 10: 7 : 6 → option (c)
Check: 25 + 45 + 35 + 15 = 120, the survey size.
Why the others are wrong
- (a)6:7 — This is Basketball : Football, the order reversed. The question names Football first, and 70 football players outnumber 60 basketball players, so the first term must be larger.
- (b)7:5 — Football's 70 is right, but 50 is not the basketball count. It is the number who do not play football (35 + 15). Basketball is 25 + 35 = 60.
- (d)5:7 — It puts football below basketball, which the table contradicts: 70 against 60. 5 : 7 matches the 'both' row against the 'basketball but not football' row, 25 : 35.
Concept
A two-sport survey splits students into four boxes that do not overlap: both, football only, basketball only and neither. The four add to the total, 120.
A sport's total is its 'only' box plus the both box, because a student who plays both is counted as a football player and as a basketball player. The 'neither' box belongs to neither total.
Key facts
- n(F) = football only + both = 45 + 25 = 70.
- n(B) = basketball only + both = 35 + 25 = 60.
- n(F ∪ B) = n(F) + n(B) − n(both) = 70 + 60 − 25 = 105, and 105 + 15 who play neither = 120.
Study next
Common traps
- Taking the 'but not' rows (45 and 35) as the sport totals and leaving out the 25 who play both.
- Writing the ratio in the wrong order: the stem names Football first.
Here the Venn regions arrive as a table rather than a diagram, and the four rows must add to the survey total of 120. Reading a 'both, but not' region from a three-circle diagram is tested at 19 Sep 2024, 16:00, Reasoning Q.18.
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