A company has a hierarchical system where for every 10 workers, there is one team lead, and for every 3 teams leads, there is one supervisor. If the company has 13 supervisors, how many workers does it have?
Choose the correct choice from the following:
A) 140
B) 321
C) 390
D) 500
E) 130
Some students may initially answer 130 to this question, especially if answering similar problems. However, that would be incorrect, as this is not a straight-forward ratio of 1:3:10.   The ratio of supervisors to team leads is 1:3, and the ratio of team leads to workers is 1:10. Therefore, the ratio of supervisors to workers is 1:30.   Therefore, 13*30=390   Answer: 390)
<result>C</result>
A company has a hierarchical system where for every 10 workers, there is one team lead, and for every 3 teams leads, there is one supervisor. If the company has 13 supervisors, how many workers does it have?