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4 years ago

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Number 18 pppllleeeaaassse hheellp

1 answer:

DanielleElmas [232]4 years ago

4 0

I wish i could help, this is some tricky stuff haha

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Choose the correct one

nalin [4]

Answer:

why does it say deleted acct

Step-by-step explanation:

if its deleted why is it still here

6 0

3 years ago

If a letter is chosen at random for the word “SUCCESS”, what is the probability that the letter will be C?

vampirchik [111]

<em>Answer</em><em>:</em>

<em>2</em><em> </em><em>out</em><em>. </em><em>of</em><em> </em><em>7</em>

<em>Explanation</em><em>:</em>

<em>First</em><em> </em><em>of</em><em> </em><em>all</em><em> </em><em>There</em><em> </em><em>are</em><em> </em><em>2</em><em> </em><em>C</em><em> </em><em> </em><em>in</em><em> </em><em>the</em><em> </em><em>word</em><em> </em><em> </em><em>and</em><em> </em><em>so</em><em> </em><em>it's</em><em> </em><em>going </em><em>to </em><em>be</em><em> </em><em>2</em><em> </em><em>out</em><em> </em><em>of </em><em>the</em><em> </em><em>total</em><em> </em><em>number</em><em> </em><em>of</em><em> </em><em>words </em><em>in</em><em> </em><em>the</em><em> </em><em>given </em><em>word</em>

<em>2</em><em> </em><em>/</em><em> </em><em>7</em><em> </em>

<em>So </em><em>that</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>probab</em><em>ility</em><em> </em>

8 0

3 years ago

The half-life of a radioactive element is 130 days, but your sample will not be useful to you after 80% of the radioactive nu

gtnhenbr [62]

Answer:

We can use the sample about 42 days.

Step-by-step explanation:

Decay Equation:

$\frac{dN}{dt}\propto -N$

$\Rightarrow \frac{dN}{dt} =-\lambda N$

$\Rightarrow \frac{dN}{N} =-\lambda dt$

Integrating both sides

$\int \frac{dN}{N} =\int\lambda dt$

$\Rightarrow ln|N|=-\lambda t+c$

When t=0, N= $N_0$ = initial amount

$\Rightarrow ln|N_0|=-\lambda .0+c$

$\Rightarrow c= ln|N_0|$

$\therefore ln|N|=-\lambda t+ln|N_0|$

$\Rightarrow ln|N|-ln|N_0|=-\lambda t$

$\Rightarrow ln|\frac{N}{N_0}|=-\lambda t$ .......(1)

$\frac{N}{N_0}=e^{-\lambda t}$ .........(2)

Logarithm:

$ln|\frac mn|= ln|m|-ln|n|$
$ln|ab|=ln|a|+ln|b|$

$ln|e^a|=a$

$ln|a|=b \Rightarrow a=e^b$
$ln|1|=0$

130 days is the half-life of the given radioactive element.

For half life,

$N=\frac12 N_0$ , $t=t_\frac12=130$ days.

we plug all values in equation (1)

$ln|\frac{\frac12N_0}{N_0}|=-\lambda \times 130$

$\rightarrow ln|\frac{\frac12}{1}|=-\lambda \times 130$

$\rightarrow ln|1|-ln|2|-ln|1|=-\lambda \times 130$

$\rightarrow -ln|2|=-\lambda \times 130$

$\rightarrow \lambda= \frac{-ln|2|}{-130}$

$\rightarrow \lambda= \frac{ln|2|}{130}$

We need to find the time when the sample remains 80% of its original.

$N=\frac{80}{100}N_0$

$\therefore ln|{\frac{\frac {80}{100}N_0}{N_0}|=-\frac{ln2}{130}t$

$\Rightarrow ln|{{\frac {80}{100}|=-\frac{ln2}{130}t$

$\Rightarrow ln|{{ {80}|-ln|{100}|=-\frac{ln2}{130}t$

$\Rightarrow t=\frac{ln|80|-ln|100|}{-\frac{ln|2|}{130}}$

$\Rightarrow t=\frac{(ln|80|-ln|100|)\times 130}{-{ln|2|}}$

$\Rightarrow t\approx 42$

We can use the sample about 42 days.

7 0

4 years ago

Ray knows that the m∠3 = m∠6. Which of the following conclusions can Ray make based on the given information? Lines l and m are

Slav-nsk [51]

If two lines are intersected by a transversal, and the alternate interior angles are equal, then the lines are parallel.

Conversely, if two lines are parallel, then the alternate interior angles formed by the transversal are equal.

So, Ray can made the conclusion that l and m are parallel because alternate interior angles are equal since m∠3 = m∠6.

4 0

3 years ago

Read 2 more answers

Aiden has three 20$ bills and two 10$ bills he wants to save a total of 95$ how much more money does he need what bills could th

kow [346]

Answer:

$15.00

A $10.00 and a $5.00 dollar bill

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers