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2 years ago

What is the value of -2/5 / 3/4?

Mathematics

1 answer:

Sveta_85 [38]2 years ago

7 0

Answer:

-8/15

Step-by-step explanation:

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Answer the following questions.

serg [7]

39 is 312% of 12.5

To find this you just divide 12.5 into 39 which gives you 3.12. To change that to a percentage you multiply by 100 which gives you 312%

7.5 is 102% of 7.38

To find this you just divide 7.38 into 7.5 which gives you 1.0162, which I rounded to 1.02. To change that to a percentage you multiply by 100 which gives you 102%

I hope this helped! :)

6 0

3 years ago

If Timmy had 4 apples his mom ate 3 and his dad is an alcoholic and his mom is in prison where did Timmy get the apples from

shusha [124]

His neighbor down the street

4 0

3 years ago

Which function represents the graph of y=10(4)x ? f g h j

garri49 [273]

G would be the correct answer

7 0

3 years ago

PLEASE HELP ME WITH THIS

guapka [62]

Can you write it out differently? I don't understand.

3 0

2 years ago

A tank contains 90 kg of salt and 1000 L of water. A solution of a concentration 0.045 kg of salt per liter enters a tank at the

Andreyy89

Answer:

Step-by-step explanation:

concentration = amount of salt/solution

A) Initial concentration= 90/1000 = 0.09

Q = quantity of salt

Q(0) = 90 kg

Inflow rate = 8 l/min

Outflow rate = 8 l/min

Solution = 1000 L at any time t.

Salt inflow = 0.045 * 8 per minute

= 0.36 kg per minute

This is mixed and drains from the tank.

Outflow = $\frac{Q(t)}{1000}$

Thus rate of change of salt

Q'(t) = inflow - outflow = $0.36-\frac{Q(t)}{1000} \\=\frac{360-Q(t)}{1000}$

Separate the variables and integrate

$\frac{1000dQ}{360-q(t)} =dt\\-1000 ln |360-Q(t)| = t+C\\ln |360-Q(t)| = -0.001+C'\\360-Q(t) = Ae^{-0.001t} \\Q(t) = 360-Ae^{-0.001t}$

Use the fact that Q(0) = 90

90 = 360-A

A = 270

$Q(t) = 360-270e^{-0.001t}$

B) Q(t) = 360-270e^-0.004 = 91.07784

C) When t approaches infinity, we get

Q(t) tends to 360

So concentration =360/1000 = 0.36

8 0

3 years ago