When substance is best use nouns proofing music room from mortal hear outside room? this shows the speed of sound in several solid mutation matter w- 5130 x...

this shows the speed of sound in several solid mutation matter

w- 5130
x - 514
y- 3813
z- 2332


when material is best use sound proofing music room from self heard outside room?

a. w
b. x
c. y
d. z

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Answers:    If you are asking for the answer, it is a.) w

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