A Survey of 200 people in a community who watched at least one of the three channels- BBC, CNN and DD- showed that 80% of the people watched DD, 22% watched BBC and 15% watched CNN. If 5% of people watched DD and CNN, 10% watched DD and BBC, then what percentage of people watched BBC and CNN only ?

• total =200
  by AUBUC formula
  (80%200)=160 similarly 22%200=44 ,15%200=30 ,5%200=10,10%200=20
  now , vienn's diagram formula
  200 = 160+44+30 -(10+20+x) -y
  where,x=bbc and cnn , y=all 3
  soving
  x-y =4
  i.e 2%
• 7 years agoHelpfull: Yes(5) No(2)
• it is a question of venn diagram
  
  a = only DD
  b = only BBC
  c= only CNN
  d = DD and BBC only
  e = DD and CNN only
  f = CNN and BBC only
  g = all channels
  
  given:
  e+g = 5............(1)
  d+g = 10..........(2)
  a+b+c+d+e+f+g = 100........(3)
  a+d+e+g = 80........(4)
  b+d+g+f = 22........(5)
  c+e+f+g = 15........(6)
  
  solving (1) &(4)
  we get a+d = 75.........(7)
  
  solving (2) &(5)
  we get b+f = 12.........(8)
  
  solving (1) &(6)
  we get c+f = 10.........(9)
  
  adding (7) &(9)
  we get a+d+c+f = 85.......(10)
  
  putting all in equation (3)
  
  we get f = 2;
  
  hence 2% watch only BBC and CNN
  2% of 200 = 4
  
  hence answer is 4.
• 7 years agoHelpfull: Yes(2) No(8)
• A=80
  B=22
  C=15
  u=union
  AuBuC=A+B+C-AB-BC-CA
  100=80+22+15-5-10-CA
  100=102-CA
  -2=-CA
  CA=2
  So answer is 2%
• 6 years agoHelpfull: Yes(1) No(1)
• approach= DD=200 * 80/100=160
  BBC=44
  CNN=30
  I+II+III=200 (given)
  I+2II+3III=160+44+30=234 now 2nd -1st equation
  so II+2III=34
  let III=x
  DD and CNN=200*5/100=10
  only DD and CNN=10-x ... here x is common in all three
  Only DD and BBC=20-x
  10-x+20-x+(only BBC and CNN)+2x=34
  so 30+(only BBC+CNN)=34
  so only BBC+CNN=4
  which is 2% of 200
  so 2%
• 6 years agoHelpfull: Yes(0) No(0)