Out of 50 teachers of a school, one teacher retires and in place of him a new teacher 35 years old joins. As a result of it average age of the teachers reduces by 0.2 years. Age of the retired teacher is :

45 years

 Age of new teacher = 35 years

Total age decreased = 50 ×0.2 = 10 years.

∴ Age of the retired teacher = Age of new teacher + Total age decreased

Age of the retired teacher = 35 + 10 = 45 years