.
30 played S
14 played both
79 played S or B
For the union of two sets, S (soccer) and B (basketball), we write
n(S U B) = n(S) + n(B) - n(S and B)
and substitute there given quantities
79 = 30 + n(B) - 14.
From this equation, we find the unknown amount
n(B) = 79 -30 + 14 = 63.
Thus the answer is: 63 students play basketball.
Solved, with explanations.
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To see many other similar solved problems, look into the lesson
- Counting elements in sub-sets of a given finite set
in this site.
Learn the subject (the basics) from there.