To determine the correct graph that represents how much water is in the leaky bucket over time, we start with the relevant information:
- The bucket initially contains 50 ml of water.
- It loses water at a rate of 15 ml every 4 minutes.
First, let's calculate the rate of loss in milliliters per minute:
\[ \text{Rate of loss} = \frac{15 \text{ ml}}{4 \text{ minutes}} = 3.75 \text{ ml/minute} \]
Now, we can create a formula for the amount of water \( W(t) \) in the bucket at time \( t \) minutes:
\[ W(t) = 50 - 3.75t \]
Next, we can plug in some values for \( t \) to see how the water level changes:
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At \( t = 0 \) minutes: \[ W(0) = 50 - 3.75(0) = 50 \text{ ml} \]
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At \( t = 4 \) minutes: \[ W(4) = 50 - 3.75(4) = 50 - 15 = 35 \text{ ml} \]
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At \( t = 8 \) minutes: \[ W(8) = 50 - 3.75(8) = 50 - 30 = 20 \text{ ml} \]
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At \( t = 12 \) minutes: \[ W(12) = 50 - 3.75(12) = 50 - 45 = 5 \text{ ml} \]
According to this information, the water level should decrease from 50 ml at \( t = 0 \) to 35 ml at \( t = 4 \), to 20 ml at \( t = 8 \), and continue to decrease.
Now looking at the graph options:
- The first graph has points at (0, 10), (2, 20), (4, 30), and (6, 40) which do not match the calculated values.
- The second graph has points at (0, 50), (4, 35), and (8, 20). This matches the calculated values.
- The third graph has points at (0, 50), (20, 35), and (40, 20), but does not correspond to the calculated intervals properly.
- The fourth graph starts from (0, 0) and does not match the start of 50 ml.
Therefore, the correct graph that shows how much water will be in the bucket over time is the second option:
- Point (0, 50) at \( t = 0 \)
- Point (4, 35) at \( t = 4 \)
- Point (8, 20) at \( t = 8 \)
This clearly indicates a decrease in water volume consistent with the calculated values.