Out of 30 teachers of a school,a teacher of age 60 years retired. In his place another teacher of age 30 years was appointed. As a result,the mean age of the teachers will
a)remain same
b)decrease by 2 years
c)decrease by 6 months
d)decrease by 1 year

• d) decreases by 1 year
  
  the decrease in the total age by (60-30)=30 years
  So average or mean age will be decrease by 30/30=1 year
• 9 years agoHelpfull: Yes(3) No(0)
• sum+60=30*30
  sum=840
  
  for 30age teacher
  sum=870
  avg=870/30
  avg=29
  
  so ans =d
• 9 years agoHelpfull: Yes(0) No(0)