Final answer:
The number of identical machines that can be added to the factory without exceeding the 90-dB limit is 10.
Step-by-step explanation:
In order to determine how many identical machines could be added to the factory without exceeding the 90-dB limit, we need to understand the relationship between sound intensity levels and the number of machines.
Sound intensity levels are measured logarithmically in decibels (dB) and can be calculated using the formula:
dB = 10 * log10(I/I0)
Where I is the intensity of the sound and I0 is the reference intensity (generally set at 10-12 W/m2).
Assuming that all the machines have the same intensity, we can set up the following equation:
80 + 10 * log10(n) = 90
Where n is the number of machines we want to add. Solving for n:
10 * log10(n) = 10
log10(n) = 1
n = 10
Therefore, you can add 10 identical machines to the factory without exceeding the 90-dB limit.