Correct Option (B)
To determine the number of students who play neither cricket nor football, the principle of inclusion-exclusion is applied. The total number of students is 100.
- Percentage of students playing cricket = 60%
- Percentage of students playing football = 30%
- Percentage of students playing both games = 10%
The percentage of students playing at least one of the two games is calculated as:
P(Cricket or Football) = P(Cricket) + P(Football) - P(Cricket and Football)
P(Cricket or Football) = 60% + 30% - 10% = 90% - 10% = 80%
This indicates that 80% of the students participate in at least one of the games.
The percentage of students who play neither game is the complement of those playing at least one game:
Percentage (Neither) = Total Percentage - P(Cricket or Football)
Percentage (Neither) = (100−80)=20%
Since the total number of students is 100, 20% of 100 students is 20 students. Therefore, 20 students play neither cricket nor football.
Incorrect Options:
Options A (25), C (18), and D (15) are incorrect. These values do not align with the accurate application of the set theory principle of inclusion-exclusion. The correct calculation, which accounts for the overlap of students playing both games, precisely yields 20 students.