Answer:
18
Step-by-step explanation:
make a ratio relation:
3 trainers : 12 dogs
x trainers : 72 dogs
3/12 = x/72
solve for x, and you get 18
Division is like sharing so 85 things that are shared between 5 people
85÷5=17 that is how much each person gets
so 17 is your answer
X+x+4+3x-9=90
5x-5=90
+5 +5
5x=95
5x/5=95/5
x=19