In a class total 34 students, 16 are have a brother, 15 are have sisters, 9 students don't have either brothers or sisters.Find the number of students having both brother and sisters.
Choose the correct choice:
A) 4  B) 5  C) 6  D) 7  E) 8
Total Number of students = 34   Let A be the Number of students have a brothers.   Let B be the number of students have a sisters.   AUB = Number of students have either brothers or sisters=34-9= 
<gadget id="calculator">34-9</gadget>
<output>25</output>
25   n(AUB)= n(A)+n(B)-n(AnB)   25=16+15-n(AnB)   n(AnB)=31-25   n(AnB)=6   The number of students having both brother and sisters = 6   ANSWER:6
<result>C</result>
In a class total 34 students, 16 are have a brother, 15 are have sisters, 9 students don't have either brothers or sisters.Find the number of students having both brother and sisters.