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Alborosie
3 years ago
11

A key board tht cost $400 is marked down 10%for a sale.what is the reducd price for the key board

Mathematics
1 answer:
allochka39001 [22]3 years ago
4 0
$350 at least i think anyways
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A gas is said to be compressed adiabatically if there is no gain or loss of heat. When such a gas is diatomic (has two atoms per
Tems11 [23]

Answer:

The pressure is changing at \frac{dP}{dt}=3.68

Step-by-step explanation:

Suppose we have two quantities, which are connected to each other and both changing with time. A related rate problem is a problem in which we know the rate of change of one of the quantities and want to find the rate of change of the other quantity.

We know that the volume is decreasing at the rate of \frac{dV}{dt}=-4 \:{\frac{cm^3}{min}} and we want to find at what rate is the pressure changing.

The equation that model this situation is

PV^{1.4}=k

Differentiate both sides with respect to time t.

\frac{d}{dt}(PV^{1.4})= \frac{d}{dt}k\\

The Product rule tells us how to differentiate expressions that are the product of two other, more basic, expressions:

\frac{d}{{dx}}\left( {f\left( x \right)g\left( x \right)} \right) = f\left( x \right)\frac{d}{{dx}}g\left( x \right) + \frac{d}{{dx}}f\left( x \right)g\left( x \right)

Apply this rule to our expression we get

V^{1.4}\cdot \frac{dP}{dt}+1.4\cdot P \cdot V^{0.4} \cdot \frac{dV}{dt}=0

Solve for \frac{dP}{dt}

V^{1.4}\cdot \frac{dP}{dt}=-1.4\cdot P \cdot V^{0.4} \cdot \frac{dV}{dt}\\\\\frac{dP}{dt}=\frac{-1.4\cdot P \cdot V^{0.4} \cdot \frac{dV}{dt}}{V^{1.4}} \\\\\frac{dP}{dt}=\frac{-1.4\cdot P \cdot \frac{dV}{dt}}{V}}

when P = 23 kg/cm2, V = 35 cm3, and \frac{dV}{dt}=-4 \:{\frac{cm^3}{min}} this becomes

\frac{dP}{dt}=\frac{-1.4\cdot P \cdot \frac{dV}{dt}}{V}}\\\\\frac{dP}{dt}=\frac{-1.4\cdot 23 \cdot -4}{35}}\\\\\frac{dP}{dt}=3.68

The pressure is changing at \frac{dP}{dt}=3.68.

7 0
3 years ago
Tres amigos: Andrés, Braulio y Ciro, juegan 3 apuestas
skelet666 [1.2K]

Answer:

La persona que ganó más dinero fue Braulio por S/.16

Step-by-step explanation:

Deje que la cantidad inicial sea Andrés X, Braulio Y y Ciro Z

Luego, dado que cada uno pierde una apuesta en el orden presentado, tenemos;

Después de la primera apuesta, tenemos;

Andrés X-Y-Z, Braulio (Y + Y), Ciro (Z + Z)

En la segunda apuesta, tenemos;

2 (X-Y-Z), 2Y - (X-Y-Z) - 2Z, 2Z + 2Z

2 (X-Y-Z), 3Y - X -Z, 4Z

En el tercero

4 (X-Y-Z), 6Y - 2X - 2Z, 4Z-2 (X-Y-Z) - (3Y - X -Z)

4 (X-Y-Z), 6Y - 2X - 2Z, 7Z - X - Y

4 (X-Y-Z) = 0.48 .............................. (1)

6Y - 2X - 2Z = 0.56 ...................... (2)

7Z - X - Y = 0.28 ............................ (3)

Multiplicamos las ecuaciones (2) por 2 y restamos la ecuación (1), tenemos;

12Y - 4X - 4Z - 4X + 4Y + 4Z = 0.56 * 2 - 0.48 = 0.64

16Y - 8X = 0.64 ...................... (4)

Multiplicamos las ecuaciones (2) por 7/2 y sumamos a la ecuación (3), tenemos;

21Y - 7X - 7Z + 7Z - X - Y = 7/2 * 0.56 + 0.28

20Y - 8X = 2.24 ...................... (5)

Restando la ecuación (4) de la ecuación (5) tenemos;

20Y - 8X - 16Y - 8X = 2.24 - 0.64 =

4Y = 1.6

Y = 1.6 / 4 = 0.4

De la ecuación (5), tenemos;

20Y - 8X = 20 * 0.4 - 8X = 2.24

8X = 8 - 2.24 = 5.76

X = 5,76 / 8 = 0,72

De la ecuación (3), tenemos;

7Z - X - Y = 7Z - 0.72 - 0.4 = 0.28

7Z = 1.4

Z = 1.4 / 7 = 0.2

Por lo tanto tienen inicialmente

X₁ = 0.72

Y₁ = 0.4

Z₁ = 0.2

Después de jugar tienen;

X₂ = 0.48

Y₂ = 0.56

Z₂ = 0.28

Los cambios son

Andrés 0.48 - 0.72 = -0.24

Braulio; 0.56 - 0.4 = 0.16

Ciro 0.28 - 0.2 = 0.08

La persona que ganó más dinero fue Braulio por S/.16

7 0
3 years ago
A football field is 100 yards long. How many feet is that?
Dmitriy789 [7]

1 yard=3 feet so 100 yard=300 feet

3 0
3 years ago
Read 2 more answers
It takes a hose 2 minutes to fill a rectangular aquarium 8 inches long, 10 inches wide, and 14 inches tall. How long will it tak
kari74 [83]

Answer:

66 minutes, or 1 hour and 6 minutes.

Step-by-step explanation:

let us first do the rectangular aquarium:

8 x 10 = 80

80 x 14 = 1120

now the second box

23 x 25 = 575

575 x 33 = 18975

we can divide the boxes volume:

18975/575 = 33

so all we have to do is times 33 by 2 which equals:

66 minutes, or 1 hour and 6 minutes.

4 0
2 years ago
James is given the diagram below and asked to prove that d is congruent to f. What would be the missing step of the proof? I onl
klemol [59]
The correct answer is B
3 0
3 years ago
Read 2 more answers
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