Answer:
The sum of the age of pupils is 81
Step-by-step explanation:
Let sum of age of 18pupils = x
Average ages = 4.5
Average = total/no. of pupil
4.5 = x/18
x = 81
47.56
16/2x4-10/5+6
8x4-10/5+6
32-10/5+6
32-2+6
30+6
36