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2 years ago

15

What is the answer to this

1 answer:

son4ous [18]2 years ago

6 0

I thin the answer is D.DF

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Initially a tank contains 10 liters of pure water. Brine of unknown (but constant) concentration of salt is flowing in at 1 lite

zhenek [66]

Answer:

Therefore the concentration of salt in the incoming brine is 1.73 g/L.

Step-by-step explanation:

Here the amount of incoming and outgoing of water are equal. Then the amount of water in the tank remain same = 10 liters.

Let the concentration of salt be a gram/L

Let the amount salt in the tank at any time t be Q(t).

$\frac{dQ}{dt} =\textrm {incoming rate - outgoing rate}$

Incoming rate = (a g/L)×(1 L/min)

=a g/min

The concentration of salt in the tank at any time t is = $\frac{Q(t)}{10}$ g/L

Outgoing rate = $(\frac{Q(t)}{10} g/L)(1 L/ min)$ $\frac{Q(t)}{10} g/min$

$\frac{dQ}{dt} = a- \frac{Q(t)}{10}$

$\Rightarrow \frac{dQ}{10a-Q(t)} =\frac{1}{10} dt$

Integrating both sides

$\Rightarrow \int \frac{dQ}{10a-Q(t)} =\int\frac{1}{10} dt$

$\Rightarrow -log|10a-Q(t)|=\frac{1}{10} t +c$ [ where c arbitrary constant]

Initial condition when t= 20 , Q(t)= 15 gram

$\Rightarrow -log|10a-15|=\frac{1}{10}\times 20 +c$

$\Rightarrow -log|10a-15|-2=c$

Therefore ,

$-log|10a-Q(t)|=\frac{1}{10} t -log|10a-15|-2$ .......(1)

In the starting time t=0 and Q(t)=0

Putting t=0 and Q(t)=0 in equation (1) we get

$- log|10a|= -log|10a-15| -2$

$\Rightarrow- log|10a|+log|10a-15|= -2$

$\Rightarrow log|\frac{10a-15}{10a}|= -2$

$\Rightarrow |\frac{10a-15}{10a}|=e ^{-2}$

$\Rightarrow 1-\frac{15}{10a} =e^{-2}$

$\Rightarrow \frac{15}{10a} =1-e^{-2}$

$\Rightarrow \frac{3}{2a} =1-e^{-2}$

$\Rightarrow2a= \frac{3}{1-e^{-2}}$

$\Rightarrow a = 1.73$

Therefore the concentration of salt in the incoming brine is 1.73 g/L

8 0

3 years ago

How many different ways can you color the Olympic rings

weqwewe [10]

Answer:

5

Step-by-step explanation:

The rings are five interlocking rings, coloured blue, yellow, black, green and red on a white field, known as the "Olympic rings". The symbol was originally created in 1913 by Coubertin.

4 0

2 years ago

13 points hurry fast answer both number 19 and 20 plz with an explination!!!!!!!

zepelin [54]

What is 19 and 20 you didn’t put anything

6 0

2 years ago

Read 2 more answers

Select all of the solutions of 4x2 - 36 = 0. If there are no solutions, select the empty set.

ruslelena [56]

Answer:

<h2>-3 ; 3</h2>

Step-by-step explanation:

4x² - 36 = 0 ⇌ (2x)² - 6² = 0 ⇌ (2x - 6)(2x + 6) = 0 ⇌ 2x - 6 = 0 or 2x + 6 = 0

⇌ x = 3 or x = -3

8 0

3 years ago

Does this number sentence accurately represent the word sentence?

djverab [1.8K]

yes, six times a number of n is 6n the greater than or equal ≥ and y plus two is y + 2

7 0

2 years ago