Let's analyze the problem step by step:

• The speed of sound in dry air at 68°F is 343.2 meters per second.
• We need to compute the number of kilometers a sound wave travels in 10 minutes.

Steps:

1. Convert 10 minutes to seconds:
   $10 \, \text{minutes} \times 60 \, \text{seconds/minute} = 600 \, \text{seconds}$

2. Calculate the distance in meters:
   Since speed is given in meters per second, the distance the sound travels in 600 seconds is:
   $343.2 \, \text{m/s} \times 600 \, \text{s} = 205,920 \, \text{meters}$

3. Convert meters to kilometers:
   There are 1000 meters in a kilometer, so:
   $205,920 \, \text{meters} \times \frac{1}{1000} = 205.92 \, \text{kilometers}$

Now, let's look at the options:

• (a) 343.2 × 60 × 10: This would give you the distance in meters, but does not include conversion to kilometers. This would give:
  $343.2 \times 60 \times 10 = 205,920 \, \text{meters}$.

• (b) 343.2 × 60 × 10 × (1/1000): This includes the correct conversion to kilometers. The expression would be:
  $343.2 \times 60 \times 10 \times \frac{1}{1000} = 205.92 \, \text{kilometers}$.
  This is the correct option.

• (c) 343.2 × (1/60) × 10: This seems incorrect as it divides by 60 instead of multiplying.

• (d) 343.2 × (1/60) × 10 × (1/1000): This also involves an incorrect division by 60, so it’s incorrect.

Conclusion:

The correct option is (b).

Would you like further details or have any questions?

Here are some related questions to consider:

1. What other factors can affect the speed of sound in air?
2. How does temperature affect the speed of sound?
3. What is the speed of sound in other mediums, like water or steel?
4. How would the result change if the time was 5 minutes instead of 10?
5. What formula relates speed, distance, and time?

Tip: Always remember to convert all units to the same system (meters to kilometers, seconds to minutes) when performing calculations.