Question

Average age of a group of 40 students is 37 years. Of a teacher is included then the average age rises by 1,then find the age of the teacher after 2 years

Answer 1

Average Age = (Total of Age of 40 students) / 40

⇒ 37 = Total of Age of 40 students / 40

⇒ Total of Age of 40 students = 37 × 40 = 1480

let current age of teacher = x years

given that if teacher age in included , then average becomes 38

⇒ 38 = ((Total of Age of 40 students ) + x) / ( 40 + 1 )      [  40 students and 1 teacher ]

⇒ 38 × 41 = 1480 + x

⇒ x = 1558 - 1480 = 78

current age of teacher = 78 years

so age of teacher after two years will be 78 + 2 = 80 years