Answer:
Ling's principal can hire new teachers in 54 different ways.
Explanation:
Since Ling's elementary school principal wants to hire some new teachers, and 6 teachers applied for one 1st grade teaching job, and 3 teachers applied for one 2nd grade teaching job, and there is also a job opening for a 3rd grade teacher, and 3 teachers applied for the job, to determine how many different ways can Ling's principal hire new teachers the following calculation has to be done:
6 x 3 x 3 = X
18 x 3 = X
54 = X
Therefore, Ling's principal can hire new teachers in 54 different ways.