Workers are digging up the road using pneumatic tools. If a single tool creates a noise level of 88 decibels a few meters away, calculate the noise level if four such tools were in operation the same distance away.
A) 176 dB
B) 90 dB
C) 352 dB
D) 94 dB
E) 92 dB

Question

Quizplus · Accepted Answer

When multiple sources of noise are present, decibel levels do not simply add up. Instead, the decibel level increases by approximately 3 dB for each doubling of the number of sources.

In this case, four tools are being used instead of one. Four is a power of two, and doubling 1 four times gives us 16. So the increase in decibel level is approximately 3 dB x 4 = 12 dB.

Therefore, the new noise level is approximately 88 dB + 12 dB = 100 dB.

The closest answer choice is D, which is 94 dB. This may be due to rounding or estimation in the calculation.

Workers Are Digging Up the Road Using Pneumatic Tools