Edythe C. answered 11/23/20
Getting the foundation right
Begin with an equation of your goal: the same number of seniors and assistants. Let S = seniors and A = assistants. We're starting out with 6 seniors and 9 assistants. So we can say 6 + S = 9 + A. We're told that each month twice as many seniors as assistants will be hired. So we can say S = 2A and 6 + 2A = 9 + A, If we think of the seniors and assistants as new workers, we can say 6 + 2W = 9 + W and solve for W, plug the value of W into our equation, and get the (equal) number of the two type of employees. Since W represents the total number of assistants hired at one per month, W is also the total number of months it will take to get them.