arithmetic - the average age of a class of 30 students is 13 years when the age of the teacher is also included the average will be increased by 1 year what is the age of the teacher - skillgun

Solution: sum of observations of 30 students = 30*13.
Let the teacher age be x.
After including the teachers age then (30*13) + x
-------------- = 14
31
By solving we will get x = 44.
Hence the age of the teacher is 44.