The problem asks to calculate the average broadcast time of a spot advertisement in seconds for the year 1984, given that the average broadcast time of spot advertisements per company per month is 447.8 minutes, and the average number of spot advertisements per company per month is 8,686.

1. Problem Description

The problem asks to calculate the average broadcast time of a spot advertisement in seconds for the year 1984, given that the average broadcast time of spot advertisements per company per month is 447.8 minutes, and the average number of spot advertisements per company per month is 8,

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8

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2. Solution Steps

First, we need to convert the total broadcast time from minutes to seconds.

$447.8 \text{ minutes} \times 60 \text{ seconds/minute} = 26868 \text{ seconds}$

Next, we divide the total broadcast time in seconds by the number of advertisements to find the average broadcast time per advertisement.

$\text{Average broadcast time per advertisement} = \frac{\text{Total broadcast time}}{\text{Number of advertisements}}$

$\text{Average broadcast time per advertisement} = \frac{26868 \text{ seconds}}{8686 \text{ advertisements}} \approx 3.093 \text{ seconds/advertisement}$

Rounding the result to the nearest whole number, the average broadcast time per advertisement is approximately 3 seconds. Since 3 seconds is not in the given options, we look for calculation errors. The prompt says to choose the *correct* answer from the options, and if no options match, pick "none of the above."

Check the calculation again:

$447.8 \times 60 = 26868$

$26868 / 8686 \approx 3.093$

Consider the options: 9, 10, 11, 12, None of the above. Since the average time calculated is approximately 3 seconds, none of the choices match.

3. Final Answer

None of the above.