<span>55 decibels. Decibels is a logarithmic scale for power and is defined as 10 log(p1/p2). However, you need to be very precise in your language if you're speaking of decibels. For instance, a doubling of POWER means an increase of 3 decibels. a doubling of VOLTAGE means an increase of 6 decibels. And because of the ear's non-linear response to sound levels, a perceived doubling of LOUDNESS is an increase of 10 decibels. So the question mentioned loudness, I'll use the increase of 10 db per doubling of volume. 8 times is 3 doubling (2*2*2 = 8). So the increase in decibels is 3 * 10 = 30 decibels. So the decibel rating of a sound that sounds 8 times louder than a sound at 25 decibels is 25 + 30 = 55 decibels.</span>

6 0

4 years ago

If $7000 is placed in account with an annual interest of 5.5% how long will it take the amount to double if the interest is comp

julsineya [31]

$A=P(1+ \frac{r}{n})^ \frac{t}{n}$
A=future amount
P=present amount
r=rate in decimal
n=number of times per year compounded
t=time in years

how many years to double
basically
A=2P at t=?
so we can simplify and ignore the pricipal given and do
$2=(1+ \frac{r}{n})^ \frac{t}{n}$
r=5.5%=0.055
n=1
t=t

$2=(1+ \frac{0.055}{1})^ \frac{t}{1}$
$2=(1+ 0.055)^t$
$2=(1.055)^t$
take the ln of both sides
$ln2=t(ln(1.055))$
divide both sides by ln1.055
$\frac{ln2}{ln1.055}=t$
use calculator to aproximate
12.9462=t
about 12.9 years

7 0

3 years ago

Un depósito de riego tiene una capacidad de 24000 litros. Un día de un depósito de riego se consumen 2/3 de él, al día siguiente

malfutka [58]

Step-by-step explanation:

Un deposito de riego tiene una capacidad de 24000 litros. Un día se consumen 2/3 del deposito. al día siguiente no se riega y el deposito recupera 1/3 de su capacidad. Al día siguiente se consumen 6000 litros. Si inicialmente el deposito contenía 18000 litros. ¿Que fracción del total queda el ultimo día?

Comenzamos:

El deposito tiene: 18.000 litros

Se consumen 2/3 del depósito: 24.000 * 2/3 = 16.000 litros

Queda: 18.000 - 16.000 = 2.000 litros

Recupera 1/3 de su capacidad: 24.000 * 1/3 = 8.000 litros

Ahora tiene: 8.000 + 2.000 = 10.000 litros

Se consumen 6.000 litros: 10.000 - 6.000 = 4.000 litros

Fracción que representa sobre el total:

\frac{4.000litros}{24.000litros}=\frac{1}{6}

24.000litros

4.000litros

5 0

3 years ago