Answer:
Russell family's sprinkler: 40 hours
Gonzales family's sprinkler: 20 hours
Step-by-step explanation:
Let's call the amount of time the Russell family's sprinkler was on by X, and the Gonzales family's sprinkler by Y.
We can then formulate the equations:
X + Y = 60
X*35 + Y*40 = 2200
We can solve this system multiplying the first equation by 35, and then subtracting the result from the second equation:
35*X + 35*Y = 2100
5*Y = 100
Y = 20
from the first equation:
X + 20 = 60
X = 40
Russell family's sprinkler: 40 hours
Gonzales family's sprinkler: 20 hours
Answer:
1) X stands for individual acts and y, group acts. 2) Each scenario describes a different period in minutes, but each one respecting their different amounts (individual and group acts). 3) 
Step-by-step explanation:
Completing with what was found:
<em> 1) Here is a summary of the scenario your classmate presented for the talent show:Main show The main show will last two hours and will include twelve individual acts and six group acts.Final show The final show will last 30 minutes and will include the top four individual acts and the top group act.The equations he came up with are: 12x+ 6y= 120, 4x+ y= 30</em>
1. What do x and y represent in this situation?
X stands for individual acts and y, group acts.
Besides that, In the system of equation, they represent the time for x, and the time for y.
2. Do you agree that your classmate set up the equations correctly? Explain why or why not.
Yes, that's right. Each scenario describes a different period in minutes, but each one respecting their different amounts (individual and group acts). Either for 120 minutes or 30 minutes length. And their sum totalizing the whole period.
3. Solving the system by Elimination

164+56−(3+4+1)
=220−(3+4+1)
=220−(7+1)
=220−8
=212
Answer:
68
Step-by-step explanation:
Add all of the numbers together then divide by the amount of numbers there are.