total 100 members are writing exam. In the 48 members are writing first exam. 45 members are writing second exam. 38 members are writing third exam. 5 members are writing all the three exams.How many members are writing 2 exams?  Select the correct option
A) 20  B) 21  C) 22  D) 23  E) 24
It's basic set theory problem using venn diagram.   Draw three intersecting circles 1,2,3. and name all the parts a,b,c,d,e,f,g. 'e' being common in all circles.   these will be the equation.   a+b+c+d+e+f+g= 100 ........(1)   a+b+d+e=48.......................(2) (members are writing first exam)   b+e+f+c=45........................(3) (members are writing second exam)   d+e+f+g=38........................(4) (members are writing third exam)   e=5......................................(5) (members are writing all the three exams)   we have to find the value of d+b+f=?   add eq 2,3,4 and put the value of a+c+g from 1.   you will get d+b+f=21.   ANSWER:21
<result>B</result>
total 100 members are writing exam. In the 48 members are writing first exam. 45 members are writing second exam. 38 members are writing third exam. 5 members are writing all the three exams.How many members are writing 2 exams?