The average salary of all staff of a school is Rs.10,000. The average salary of 20 teaching staff is Rs.12,000 and that of non-teaching staff is Rs. 5000, the number of non - teaching staff is:

The average salary of all staff of a school is Rs.10,000. The average

1.	The average salary of all staff of a school is Rs.10,000. The average salary of 20 teaching staff is Rs.12,000 and that of non-teaching staff is Rs. 5000, the number of non - teaching staff is:
A.	7
B.	12
C.	10
D.	8
Answer» E.