Sound Intensity of a workplace

[tics]

Accoding to US government regulations, the maximum sound intensity levels in the workplace is 90,0 dB. Within one factory, 32 ihdentical machines produce a sound intensity level of 92,0 dB. How many machines must be removed to bring the factory into compliance with the regulation?

Possible answers:
a) 2
b) 8
c) 16
d) 24

 

[Integral]

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[tics]

Accoding to US government regulations, the maximum sound intensity levels in the workplace is 90,0 dB. Within one factory, 32 ihdentical machines produce a sound intensity level of 92,0 dB. How many machines must be removed to bring the factory into compliance with the regulation?

Possible answers:
a) 2
b) 8
c) 16
d) 24

My attempt:

β_1=90.0 dB,β_2=92.0 dB
B2-B1= 10log(I1/I0)-10log(I2/I0)
=10log(I2/I0/I1/I0)
=10log(I2/I1)
0.2 =log(I2/I1)
Therefore: I2/I1=10^(0.2)= 1.58
32 machines/1.58 ≈20
The number of machines that must be removed is 32-20=12
Is that right?