Final answer:
The loudness of an 80 dB sound wave is roughly 5 times more than the loudness of a 40 dB sound wave.
Step-by-step explanation:
The loudness of a sound wave is measured in decibels (dB), which represents the intensity or strength of the sound. Each factor of 10 in intensity corresponds to a 10 dB difference.
So, to find out roughly how many times more the loudness of an 80 dB sound wave is than a 40 dB sound wave, we need to calculate the difference in decibels.
From the given information, we know that a difference of 7 dB corresponds to a factor of five in intensity. Therefore, the 80 dB sound wave is roughly 5 times more intense than the 40 dB sound wave.