Question

The average age of 30students is 9yeans the age of their teacher is included, it become 10 yeans what is the age of teacher?​

Answer 1

Answer:

average of 30 students is 9 years

then sum of ages of all students is 270

when teacher age is included then no of people is 31

then sum of their ages is 310

then teacher age is 310 - 270

40