In a class of 30 students, 18 study French, 15 study calligraphy and 5 study neither. How many students study both?
Answer and explanation
Correct answer: B. 8
- Step 1: The number who study at least one subject is 30 - 5 = 25. Step 2. n(F and C) = 18 + 15 - 25 = 8. Answer: 8. Why not the others: 3 is 18 - 15, the difference between the two groups; 10 subtracts the 5 from the total again; and 13 is 18 - 5, which ignores the calligraphy group.
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