Hello there! I can help you! So there is one blue counter added to two green counters. To solve this problem, we can write and solve an equation. Set it up like this:
12 + 1x = 8 + 2x
We do this, because there are already some of each color in the bag. 1x makes one counter each and 2x is two counters for every blue counter in the bag. Let's solve it. Subtract 1x from each side. 1x - 1x cancels out. 2x - 1x is 1x or just simply x. That simplifies to 12 = 8 + x. Subtract 8 from each side to get the variable by itself. 8 - 8 cancels out. 12 - 8 is 4. That leaves 4 = x. Nothing else needs to be done. Let's plug the value in and see if it works. 1 * 4 is 4. 12 + 4 is 16. 2 * 4 is 8. 8 + 8 is 16. 16 = 16. There. x = 4. 4 blue counters and 8 green counters were added to the bag.
First, we are going to calculate her monthly off-peak usage:
1,185 kWh - 500 kWh = 685 kWh
Now that we know her monthly electricity consumption is 500 kWh on-peak and 685 kWh off-peak, lets calculate the cost of each plan:
<span>
Standard use plan</span>1,185 kWh - 600 kWh = 585 kWh
- For the first 600 KWh:

Since 100 cents = 1 dollar,

= $51
- For the remaining 585 kWh:

Since 100 cents = 1 dollar,

= $64.35
Total cost of the standard use plan: $51 + $64.35 = $115.35
Interval use plan
- On-peak hours:

Since 100 cents = 1 dollar,

= $80
- Off-peak hours:

Since 100 cents = 1 dollar,

= $27.40
Total cost of the interval use plan: $80 + $27.40 = $107.40
We can conclude that:
1. The new interval plan will be better for Anna since she will save $7.95 per month in her electric bill.
2. The correct answer is: <span>
b.standard use plan - $115.35; interval use plan - $107.40</span>