In housing society, half of familiars have a single child per family, while the
remaining half have two children per family. The probability that a child picked
at random has a sibling is _____.

• Let total no. of families be x.
  No. of children not having siblings= x/2.
  No. of children having siblings= 2*No. of families having 2 children=2*(x/2)=x
  Total children= x+x/2=(3x)/2.
  Probability that a child pickedat random has a sibling
  = (No. of children having siblings)/(Total no. of children)
  = x/(3x/2)= 2/3=0.666
• 10 years agoHelpfull: Yes(6) No(0)
• 0.66
  1/(2+1)
  
• 10 years agoHelpfull: Yes(0) No(3)