Question

The average ago of a child in a class of 35 is 11 the average age including the teacher is 12. How old is the teacher

Answer 1

Answer:

average= total sum/no.of observation

total sum= average× no. of observation

= 11×35

385

new average= 12

new no. of observation = 35+1=36

new total sum =36×12=432

now age of teacher =432-385

=47answer

another way of solving

old average+new no. of observation×increment in average

11+36×{12-11}

11+36

47 answer