The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by3 months. Find the age of the teacher.

• 25 year
  avg of 39 student = 15 yrs
  Total age of 39 students=39*15= 585 yrs
  Avg age of 39 students + teacher =15+3/12=15.25 yrs
  so the total age of (39 student+1 teacher) or 40 persons=
  40*15.25=610 yrs
  so age of teacher=610-585=25 years
• 10 years agoHelpfull: Yes(52) No(0)
• 25 year
  avg of 39 student is 15 so 585
  15+3/12=61/4
  now the total is(39 student+1 teacher)=40
  40*61/4=610
  so age of teacher=610-585=25 years
• 10 years agoHelpfull: Yes(10) No(2)
• simple avg increases 3month
  avg=no.of student/total student
  so increase 3months on every student and teacher i.e (39+1)
  so 40*3=120months(10 YEARS)
  already avg given as 15years
  then 10y+15y = 25years
• 10 years agoHelpfull: Yes(5) No(2)
• 35 year
  avg of 39 student is 15 so 585
  15+3/12=61/4
  now the total is(39 student+1 teacher)=40
  40*61/4=610
  so age og teacher=610-585=35
• 10 years agoHelpfull: Yes(1) No(17)
• sum of the ages of 39 students =15*39=585
  including teacher total number of members =40
  and average of 40 members =15.3 yrs
  let the age of teacher be x yrs
  ages of 39 students +age of teacher=585+x
  585+x=15.3*40
  x=27 yrs
• 9 years agoHelpfull: Yes(1) No(8)
• teacher age(15 years 3 months+39*3 months)
  15 years 120 months ...
  =15+(120/12) years
  =25 years
  
• 10 years agoHelpfull: Yes(0) No(0)
• 25 yrs
  total age of student=39*15=585
  increase in avrg age=15 1/4
  3month=3/12 yrs=1/4
  now total age=40*15.25=610
  teacher age=610-585=25 ans
• 8 years agoHelpfull: Yes(0) No(0)