In Aditya hospital, the average salary of 9 nurses is Rs. 3600 while the average salary of 11 ward boys is Rs. 4400 and the average salary of all doctors is Rs. 22000. If average salary of entire staff is Rs. 7632, then find the number of doctors working in Aditya hospital.
1
25
2
7
3
15
4
5
5
10