Answer: 130
Step-by-step explanation:
Let x be the original number of hip- hop CDs in the music store.
Given : A music store has sold 3/5 of their hip-hop CDs, but 10 were returned.
i.e. The number of hip- hop CDs in the store will be :
Original No. of CDs - CDs sold + CDs Returned
If the store has 62 Hip-Hop CDs now , then required euation will be :-
Subtract 10 from both sides , we get
Hence, the number of CDs they originally have = 130
Answer:
150.51 dB
Step-by-step explanation:
Data provided in the question:
decibel level of sound at 161 km distance = 180 dB
d₁ = 161 km
d₂ = 4800 km
I₁ = 180 db
The formula for intensity of sound is given as:
I =
and the relation between intensity and distance is given as:
I ∝
or
Id² = constant
thus,
I₁d₁² = I₂d₂²
or
therefore,
I =
or
I =
or
I = 20 × (-1.474)
or
I = -29.49
Therefore,
the decibel level on Rodriguez Island, 4,800 km away
= 180 - 29.49
= 150.51 dB