Add the like terms.
12r+11r-4r= 19r
5s+9s=14s
-7t=-7t
19r+14s-7t
Answer:
k=30
Step-by-step explanation:
The number of mice vary inversely with cats. This is written as:

When there are 3r-19 cats, there are 2r+1 mice

When there are 6r-27 mice, there are r-5 cats.

Taking the values of k above, we have:

Therefore:

Answer: A
Why: She gets a base $159 each day, plus 6% (0.06) of each sale, x. 0.06x+159=her pay