GIVEN:The AVERAGE age of 30 STUDENTS = 15 yearsAverage age INCREASES by 1 year If the age of the teacher is also included.Concept:Total age = Average × total numberCalculation:Total age of 30 students = 30 × 15 = 450 yearsNew average after addition of teacher = 15 + 1 = 16 yearsTotal number = 30 + 1 = 31Total age of 31 people = 31 × 16 = 496 years∴ Age of teacher = Total age of 31 people - Total age of 30 students = 496 - 450 = 46 yearsAge of teacher = Average age + number of members including the teacher × increment in average age⇒ Age of teacher = 15 + 1 × 31 = 46 years