It is given in the question that
Ms. Velez will use both x gray bricks and y red bricks to build a wall around her garden. Gray bricks cost $0.45 each and red bricks cost $0.58 each. She can spend up to $200 on her project, and wants the number of red bricks to be less than half the number of gray bricks.
Maximum she can spend is $200. That is
And
And that's the required inequalities .
The intensity of sound which the decibel level of the sound measures 156 is 3.981 × 10³ W/m²
Decibel level, dB = 10log₁₀(I/I₀) where dB = decibel level = 156, I = intensity at 156 dB and I₀ = 10⁻¹² W/m².
Since we require I, making I subject of the formula, we have
dB/10 = log₁₀(I/I₀)
Substituting the values of the variables into the equation, we have
I = 3981.072W/m²
I = 3.981 × 10³ W/m²
So, the intensity of sound which the decibel level of the sound measures 156 is 3.981 × 10³ W/m²
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