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3 years ago

8

Everyone at your school has to take one art class, so 115 students take glass blowing, 90 students take cave painting, and 15 st

udents take both. The wisest 120 students take photography for an easy A. How many total students are at your school?

1 answer:

emmainna [20.7K]3 years ago

5 0

There are 340 students at your school.
115 + 90 + 15 + 120 = 340

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Trey received a $15.00 gift card for a photo center. He used it to buy prints that cost 8 cents each. The remaining balance, B i

Ostrovityanka [42]

Answer:

$13.40

Step-by-step explanation:

Multiply 0.08 by 20 to get 1.60 then subtract that from 15 to get 13.40

8 0

4 years ago

Solve Using Dirac Deltla/discontinuous forcing

Jet001 [13]

Let $A(t)$ denote the amount of salt in the tank at time $t$ . We're told that $A(0)=0$ .

For $0\le t\le15$ , the salt flows in at a rate of (1/5 lb/gal)*(5 gal/min) = 1 lb/min. When the regulating mechanism fails, 20 lbs of salt is dumped and no more salt flows for $t>15$ . We can capture this in terms of the unit step function $u(t)$ and Dirac delta function $\delta(t)$ as

$\text{rate in}=u(t)-u(t-15)+20\delta(t-15)$

(in lb/min)

The salt from the mixed solution flows out at a rate of

$\text{rate out}=\left(\dfrac{A(t)\,\mathrm{lb}}{50+(5-5)t\,\mathrm{gal}}\right)\left(5\dfrac{\rm gal}{\rm min}\right)=\dfrac A{10}\dfrac{\rm lb}{\rm min}$

Then the amount of salt in the tank at time $t$ changes according to

$\dfrac{\mathrm dA}{\mathrm dt}=u(t)-u(t-15)+20\delta(t-15)-\dfrac A{10}$

Let $\hat A(s)$ denote the Laplace transform of $A(t)$ , $\hat A(s)=\mathcal L_s\{A(t)\}$ . Take the transform of both sides to get

$s\hat A(s)-A(0)=\dfrac1s-\dfrac{e^{-15s}}s+20e^{-15s}-\dfrac1{10}\hat A(s)$

Solve for $\hat A(s)$ , then take the inverse of both sides.

$\hat A(s)=\dfrac{\frac{10-10e^{-15s}}{s^2}+\frac{200e^{-15s}}s}{10s+1}$

$\implies\boxed{A(t)=10-10e^{-t/10}+\left(30e^{3/2-t/10}-10\right)u(t-15)}$

7 0

4 years ago

The frog population at a lake doubles every week. The population can be modeled by

marta [7]

The answer is C. The rate the population increases. The 960 in the equation represents the population at a certain number of weeks which is x. The starting population describes the quantity 15. The number of weeks that have passed is described as the 6 weeks.

The equation would be described as: f(x) =15*(2^x) and f(x) =960

8 0

3 years ago

Read 2 more answers

Simplify (7x) - (-2x).<br> O 5x<br> 0 -5x<br> O 9x<br> 0-9x<br> NEXT QUESTION<br> 2<br> ASK FOR UEL

marysya [2.9K]

Answer:

9x

Step-by-step explanation:

Since you are subtracting a negative from a positive you would get 9

3 0

4 years ago

Work out the volume of this sphere 4.7cm

Damm [24]

Answer:

435cm³

is my answer correct?

im pretty sure it is...

what is the 4.7cm the radius or circumference

if its the circumferance the answer is 1.753

Step-by-step explanation:

3 0

3 years ago