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2 years ago

Segments AB and CD coincide.

Mathematics

2 answers:

Westkost [7]2 years ago

7 0

Answer: it’s the first one

Step-by-step explanation:

laila [671]2 years ago

4 0

Answer:

Step-by-step explanation:

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Problem 10: A tank initially contains a solution of 10 pounds of salt in 60 gallons of water. Water with 1/2 pound of salt per g

AysviL [449]

Answer:

The quantity of salt at time t is $m_{salt} = (60)\cdot (30 - 29.833\cdot e^{-\frac{t}{10} })$ , where t is measured in minutes.

Step-by-step explanation:

The law of mass conservation for control volume indicates that:

$\dot m_{in} - \dot m_{out} = \left(\frac{dm}{dt} \right)_{CV}$

Where mass flow is the product of salt concentration and water volume flow.

The model of the tank according to the statement is:

$(0.5\,\frac{pd}{gal} )\cdot \left(6\,\frac{gal}{min} \right) - c\cdot \left(6\,\frac{gal}{min} \right) = V\cdot \frac{dc}{dt}$

Where:

$c$ - The salt concentration in the tank, as well at the exit of the tank, measured in $\frac{pd}{gal}$ .

$\frac{dc}{dt}$ - Concentration rate of change in the tank, measured in $\frac{pd}{min}$ .

$V$ - Volume of the tank, measured in gallons.

The following first-order linear non-homogeneous differential equation is found:

$V \cdot \frac{dc}{dt} + 6\cdot c = 3$

$60\cdot \frac{dc}{dt} + 6\cdot c = 3$

$\frac{dc}{dt} + \frac{1}{10}\cdot c = 3$

This equation is solved as follows:

$e^{\frac{t}{10} }\cdot \left(\frac{dc}{dt} +\frac{1}{10} \cdot c \right) = 3 \cdot e^{\frac{t}{10} }$

$\frac{d}{dt}\left(e^{\frac{t}{10}}\cdot c\right) = 3\cdot e^{\frac{t}{10} }$

$e^{\frac{t}{10} }\cdot c = 3 \cdot \int {e^{\frac{t}{10} }} \, dt$

$e^{\frac{t}{10} }\cdot c = 30\cdot e^{\frac{t}{10} } + C$

$c = 30 + C\cdot e^{-\frac{t}{10} }$

The initial concentration in the tank is:

$c_{o} = \frac{10\,pd}{60\,gal}$

$c_{o} = 0.167\,\frac{pd}{gal}$

Now, the integration constant is:

$0.167 = 30 + C$

$C = -29.833$

The solution of the differential equation is:

$c(t) = 30 - 29.833\cdot e^{-\frac{t}{10} }$

Now, the quantity of salt at time t is:

$m_{salt} = V_{tank}\cdot c(t)$

$m_{salt} = (60)\cdot (30 - 29.833\cdot e^{-\frac{t}{10} })$

Where t is measured in minutes.

7 0

3 years ago

A car used 5 2/3 gallons of fuel on a 3 hour trip. How many gallons were used each hour?

mr_godi [17]

Answer:

2. 1 8/9 gallons

Step-by-step explanation:

5 2/3 divided by 3

5.66666667/3 = 1.88888889

.88888889 = 8/9

1 + 8/9 = 1 8/9

5 0

2 years ago

Stefan sells Jin a bicycle for $176 and a helmet for $16. The total cost for Jin is 160% of what Stefan spent originally to b

Elis [28]

Answer:

Stefan originally paid $120 for the bicycle and helmet.

He made $72 by selling them to Jin.

Step-by-step explanation:

Given that:

Selling price of bicycle = $176

Selling price of helmet = $16

Total price = 176+16 = $192

This is 160% of what Stefan paid originally.

Let,

x be the original amount paid by Stefan.

160% of x = 192

$\frac{160}{100}x=192\\1.6x=192$

Dividing both sides by 1.6

$\frac{1.6x}{1.6}=\frac{192}{1.6}\\x=120$

Original amount paid by Stefan = $120

Profit = 192 - 120 = $72

Hence

Stefan originally paid $120 for the bicycle and helmet.

He made $72 by selling them to Jin.

3 0

2 years ago

Solve | x | < 10

Neko [114]

Answer:

Right answer is B) x>-10 and x<10

8 0

3 years ago

Please help ASAP

Ivan

Answer:

(5, 12, 13)

Step-by-step explanation:

5^2+12^2=25+144=169=13^2

5^2+12^2=13^2

5 0

2 years ago