The average salary of all the workers in a workshop is $8000. The average salary of 7 technicians is $12000 and the average salary of the rest is $6000. The total number of workers in the shop is?  Select the correct option
A) 15	B) 18	C) 21	D) 25	E) 31

Rationale: let the total number of workers be x 8000 x = 12000 * 7 + 6000 ( x - 7 ) x = 21 answer is c
Answer: C