Question

The average of a child 35 classes is 11 the average include techer is 12.how old the teacher

Answer 1

Step-by-step explanation:

Average age of 30 students=9

Total age of 30 students = 30 ×9=270 (1)

Average including teacher (31 person, 30 students + 1 teacher) =10

Total age including teacher=31×10=310

Age of 30 students + age of teacher =310

By(1) Replace Age of 30 students with 270

270 + Age of teacher = 310

Age of teacher =310–270=40.