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Created February 1, 2025 16:38
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r1-balance
<USER>
## 6. The Lost Scale Pan
Robert lost the right pan of his balance scale and had to use a different one — slightly heavier than the original. Now, with empty pans, his scale does not show balance.
However, Robert noticed that when he places a full bottle of juice on the right pan and 9 identical empty bottles on the left pan, the scale is balanced.
The same happens when Robert places two empty bottles on the right pan and a bottle filled halfway with juice on the left pan.
**How many times heavier is the full bottle of juice compared to an empty bottle?**
<ASSISTANT>
Let's tackle the problem systematically by defining the variables and setting up equations based on the given information.
### Step 1: Define the Variables
- Let \( E \) be the weight of an empty bottle.
- Let \( J \) be the weight of the juice in a full bottle.
- Therefore, the weight of a full bottle is \( E + J \).
- Let \( P \) be the weight of the right pan (which is heavier than the left pan).
### Step 2: Analyze the First Scenario
**Scenario 1:**
- Right pan: 1 full bottle (\( E + J \))
- Left pan: 9 empty bottles (\( 9E \))
- The scale is balanced.
Since the right pan is heavier by \( P \), the equation for balance is:
\[
(E + J) + P = 9E
\]
Simplifying:
\[
E + J + P = 9E \\
J + P = 8E \quad \text{(Equation 1)}
\]
### Step 3: Analyze the Second Scenario
**Scenario 2:**
- Right pan: 2 empty bottles (\( 2E \))
- Left pan: 1 bottle filled halfway with juice (\( E + \frac{J}{2} \))
- The scale is balanced.
Again, considering the heavier right pan by \( P \), the equation for balance is:
\[
2E + P = E + \frac{J}{2}
\]
Simplifying:
\[
2E + P = E + \frac{J}{2} \\
E + P = \frac{J}{2} \quad \text{(Equation 2)}
\]
### Step 4: Solve the Equations
We have two equations:
1. \( J + P = 8E \)
2. \( E + P = \frac{J}{2} \)
Let's solve these equations simultaneously.
**From Equation 2:**
\[
E + P = \frac{J}{2} \\
\Rightarrow P = \frac{J}{2} - E \quad \text{(Equation 3)}
\]
**Substitute Equation 3 into Equation 1:**
\[
J + \left( \frac{J}{2} - E \right) = 8E \\
J + \frac{J}{2} - E = 8E \\
\frac{3J}{2} - E = 8E \\
\frac{3J}{2} = 9E \\
3J = 18E \\
J = 6E
\]
### Step 5: Determine the Weight Ratio
We found that \( J = 6E \). Therefore, the weight of a full bottle is:
\[
E + J = E + 6E = 7E
\]
So, a full bottle is \( 7 \) times heavier than an empty bottle.
### Conclusion
After setting up and solving the equations based on the given scenarios, we determined that a full bottle of juice is **7 times heavier** than an empty bottle.
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