Decibel and equations

sonrays06

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Jan 22, 2021
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1. Suppose you make an investment of $1000 that you are not allowed to cash in for 30 years. Unfortunately, the value of the investment decreases by 10% per year.
How long will it be before your investment decreases to half its original value? Round your answer to one decimal place.

2. Suppose that inflation is 2.5% per year. This means that the cost of an item increases by 2.5% each year. Suppose that a jacket cost $100 in the year 2017.
How long (in yr) will it take for the jacket to cost $600? Round your answer to the nearest year.

3. A speaker is playing music at 80 decibels. A second speaker playing the same music at the same decibel reading is placed beside the first.
What is the decibel reading of the pair of speakers? (Round your answer to the nearest whole number.)

4. Suppose a speaker is playing music at 65 decibels.
If two more identical speakers (playing the same music) are placed beside the first, what is the resulting decibel level of the sound? (Round your answer to the nearest whole number.)

5. A certain population is growing according to the formula: N = 1410 × 1.03t.
What is the tripling time for this population? Round your answer to one decimal place.

6. If an adjustment raises the sound on your television by 7 decibels, how is the relative intensity of the sound affected? Round your answer to one decimal place.
The relative intensity is multiplied by ?
 
1. Suppose you make an investment of $1000 that you are not allowed to cash in for 30 years. Unfortunately, the value of the investment decreases by 10% per year.
How long will it be before your investment decreases to half its original value? Round your answer to one decimal place.

2. Suppose that inflation is 2.5% per year. This means that the cost of an item increases by 2.5% each year. Suppose that a jacket cost $100 in the year 2017.
How long (in yr) will it take for the jacket to cost $600? Round your answer to the nearest year.

3. A speaker is playing music at 80 decibels. A second speaker playing the same music at the same decibel reading is placed beside the first.
What is the decibel reading of the pair of speakers? (Round your answer to the nearest whole number.)

4. Suppose a speaker is playing music at 65 decibels.
If two more identical speakers (playing the same music) are placed beside the first, what is the resulting decibel level of the sound? (Round your answer to the nearest whole number.)

5. A certain population is growing according to the formula: N = 1410 × 1.03t.
What is the tripling time for this population? Round your answer to one decimal place.

6. If an adjustment raises the sound on your television by 7 decibels, how is the relative intensity of the sound affected? Round your answer to one decimal place.
The relative intensity is multiplied by ?
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