Toni and Nicky each earn a weekly salary

The Chang family is on their way home from a cross-country road trip. During the trip, the function D(t) = 2,280 - 60t can be us

nordsb [41]

Answer:

C

Step-by-step explanation:

I took the test and got it correct.

7 0

2 years ago

a rectangle pyramid fits exactly on top of a rectangular prism. the prism has a length of 18 cm, a width of 6 cm, and a height o

irina1246 [14]

To find the volume of the prism you are going to use the formula V=WxLxH.
When you plug in your numbers you should get V= 18x6x9 which ends up equaling 972.

Now that you have that you need to find the volume of the pyramid using the formula V= L x W x H /3 and when you plug that in it looks like
V= 18 x 6 x 15 /3

Upon simplifying that you get 540.

Now you have the volume of your rectangular prism and your rectangular pyramid add them together and you should get 1512

I recommend drawing it out... it helps a lot:)

4 0

2 years ago

Two identical decks of 52 cards are mixed together, yielding a stack of 104 cards. How many different ways are there to order th

kumpel [21]

Answer:

here the order will be 104! = $1.029e^{166}$

Step-by-step explanation:

since the cards are to arranged in no particular order that is why we used combination to find the result.

Combination can simply be explained as the method of selecting items from a collection of items where the order of the selections does not matter.

7 0

1 year ago

A large tank is partially filled with 100 gallons of fluid in which 20 pounds of salt is dissolved. Brine containing 1 2 pound o

Valentin [98]

Answer:

47.25 pounds

Step-by-step explanation:

$\dfrac{dA}{dt}=R_{in}-R_{out}$

First, we determine the Rate In

Rate In=(concentration of salt in inflow)(input rate of brine)

$=(0.5\frac{lbs}{gal})( 6\frac{gal}{min})\\R_{in}=3\frac{lbs}{min}$

Change In Volume of the tank, $\frac{dV}{dt}=6\frac{gal}{min}-4\frac{gal}{min}=2\frac{gal}{min}$

Therefore, after t minutes, the volume of fluid in the tank will be: 100+2t

Rate Out

Rate Out=(concentration of salt in outflow)(output rate of brine)

$R_{out}=(\frac{A(t)}{100+2t})( 4\frac{gal}{min})\\\\R_{out}=\frac{4A(t)}{100+2t}$

Therefore:

$\dfrac{dA}{dt}=3-\dfrac{4A(t)}{100+2t}\\\\\dfrac{dA}{dt}=3-\dfrac{4A(t)}{2(50+t)}\\\\\dfrac{dA}{dt}=3-\dfrac{2A(t)}{50+t}\\\\\dfrac{dA}{dt}+\dfrac{2A(t)}{50+t}=3$

This is a linear differential equation in standard form, therefore the integrating factor:

$e^{\int \frac{2}{50+t}dt}=e^{2\ln|50+t|}=e^{\ln(50+t)^2}=(50+t)^2$

Multiplying the DE by the integrating factor, we have:

$(50+t)^2\dfrac{dA}{dt}+(50+t)^2\dfrac{2A(t)}{50+t}=3(50+t)^2\\\{(50+t)^2A(t)\}'=3(50+t)^2\\$Taking the integral of both sides\\\int \{(50+t)^2A(t)\}'= \int 3(50+t)^2\\(50+t)^2A(t)=(50+t)^3+C $ (C a constant of integration)\\Therefore:\\A(t)=(50+t)+C(50+t)^{-2}$

Initially, 20 pounds of salt was dissolved in the tank, therefore: A(0)=20

$20=(50+0)+C(50+0)^{-2}\\20-50=C(50)^{-2}\\C=-\dfrac{30}{(50)^{-2}} =-30X50^2=-75000$

Therefore, the amount of salt in the tank at any time t is:

$A(t)=(50+t)-75000(50+t)^{-2}$

After 15 minutes, the amount of salt in the tank is:

$A(15)=(50+15)-75000(50+15)^{-2}\\=47.25$ pounds$

8 0

2 years ago

The label on the car's antifreeze container claims to protect the car between −40°C and 140°C. To covert Celsius temperature to

sergejj [24]

Answer:

-40 < t < 284

Step-by-step explanation:

The antifreeze protects the car between −40°C and 140°C.

Using t for temperature, the compound inequality of the Celsius temperature range is:

-40 < t < 140

The conversion formula is given to find degrees C in given degrees F. We can solve the formula for F, so we get degrees F in terms of degrees C.

C = (5/9)(F - 32) <------ conversion formula from deg F to deg C

Solve for F:

(9/5)C = F - 32

(9/5)C + 32 = F

F = (9/5)C + 32 <------ conversion formula from deg C to deg F

Now we convert -40 deg C to deg F using the formula we just derived.

F = (9/5)C + 32

F = (9/5)(-40) + 32

F = -72 + 32

F = -40

-40 deg C = -40 deg F

(This is not a mistake or a typo. -40 deg C really is the same as -40 deg F.)

Now we convert 140 deg C to deg F using the formula we just derived.

F = (9/5)C + 32

F = (9/5)(140) + 32

F = 252 + 32

F = 284

140 deg C = 284 deg F

Now we rewrite the compound inequality with Fahrenheit temperatures.

-40 < t < 284

4 0

2 years ago