To find the total decrease in the water level over 5 hours (or 18,000 seconds), we can perform the following calculation:
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Determine the decrease per second: \[ \text{Decrease per second} = 3.6 \times 10^{-2} \text{ mm/s} \]
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Determine the total time: \[ \text{Total time} = 18,000 \text{ seconds} = 1.8 \times 10^4 \text{ seconds} \]
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Calculate the total decrease: \[ \text{Total decrease} = \text{Decrease per second} \times \text{Total time} = (3.6 \times 10^{-2}) \times (1.8 \times 10^4) \]
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Perform the multiplication: \[ = 3.6 \times 1.8 \times 10^{-2 + 4} = 6.48 \times 10^{2} \]
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Express in scientific notation: Since \(6.48\) is not in the standard format for scientific notation (which requires a leading digit smaller than 10), we rewrite it as: \[ 6.48 \times 10^{2} = 6.48 \times 10^2 \text{ mm} = 6.48 \times 100 \text{ mm} = 648 \text{ mm} \] However, to retain the scientific notation form, we must convert \(6.48\) appropriately: \[ 6.48 = 6.48 \times 10^0 \quad \text{(if needed)} \] Thus, we finalize it as: \[ \approx 6.48 \times 10^2 mm \]
Final answer:
- Select 6.48 for the first response area.
- Select 2 for the second response area.
- Therefore, the decrease in the water level is approximately \(6.48 \times 10^2 \text{ mm}\).