Answer:
14
Step-by-step explanation:
5x-7=3x+21
2x=28
x=14
<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>

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

r=5.5%=0.055
n=1
t=t



take the ln of both sides

divide both sides by ln1.055

use calculator to aproximate
12.9462=t
about 12.9 years
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
=
6
1