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Ipatiy [6.2K]
3 years ago
9

A radioactive substance decays according to the formula A=A0e^kt

Mathematics
1 answer:
Sholpan [36]3 years ago
4 0
Without needing fancy formulas, we can conclude that after 10 years, half of the substance will be left.  So, we can make our own formula:
amount remaining = 1 / 2^(years/10)
So, after 5 years
amount remaining = 1 / 2^(5/10)
amount remaining = 1 / 2^(.5)
amount remaining = 1 / <span> <span> <span> 1.414213562 </span>
</span></span><span>amount remaining = 0.70711 * 20 grams
</span><span><span><span><span>amount remaining = </span>14.1421356237 grams

</span></span></span>


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Retha Davidson works for a word processing center keying straight copy.
Nataliya [291]

Using proportions, it is found that:

  • In an 8-hour day, she keys 48 pages.
  • For a day, her gross earnings are of $72.
  • For a week, her gross earnings are of 72 x 7 = $504.

<h3>Proportions:</h3>

This question is solved using the proportions given, which are:

  • Payment of $1.50 per page of 30 lines.
  • Retha keys 6 pages per hour.

Hence, in an 8-hour day, she keys 6 x 8 = 48 pages.

Since she earns $1.50 per page, for a day, her gross earnings are of 48 x 1.5 = $72.

Considering a week has 7 days, for a week, her gross earnings are of 72 x 7 = $504.

To learn more about proportions, you can take a look at brainly.com/question/24372153

5 0
2 years ago
I am stuck on these last four questions please help if possible.
zloy xaker [14]

Answer:

Step-by-step explanation:

9). -2.2(4 - 1.9x) = 3.3(0.2x - 0.8)

    -8.8 + 2.2(1.9x) = 0.66x - 2.64

    -8.8 + 4.18x = 0.66x - 2.64

     4.18x - 0.66x = 8.8 - 2.64

     3.52x = 6.16

     x = 1.75

10). 3.2(1 + 2.6x) = 2.4(x - 3.6)

     3.2 + 8.32x = 2.4x - 8.64

     8.32x - 2.4x = -3.2 - 8.64

     5.92x = -11.84

      x = 2

11). 4.6(2x - 5.5) = 3.9 + 0.8(1 + 5.5x)

     9.2x - 25.3 = 3.9 + 0.8 + 4.4x

     9.2x - 25.3 = 4.7 + 4.4x

     9.2x - 4.4x = 25.3 + 4.7

     4.8x = 30

      x = 6.25

12). 0.2(3x + 2.5) - 4.9 = 3.8 - 2.2(x - 5.5)

     0.6x + 0.5 - 4.9 = 3.8 - 2.2x + 12.10

     0.6x - 4.4 = -2.2x + 15.90

     0.6x + 2.2x = 15.90 + 4.4

     2.8x = 20.30

     x = 7.25

4 0
3 years ago
there are 500 hundred pages. if the book has 25 chapters and each chapter is 20 pages long. what is the chance that of randomly
nataly862011 [7]
20/500
0.04 of a chance
because 1 chapter has 20 pages and the book has 500
so the chance of you flipping to chapter 12 out of 500 pages is 4% of a chance
6 0
3 years ago
What is the equation of the line written in general form?
Irina18 [472]
I think its b or c but my best guess would be b
7 0
3 years ago
Determine which of the following formulas hold for all invertible n×n matrices A and B.
garik1379 [7]

Answer:

1 hold

2 hold

3 does not hold

4 hold

5 hold

6 hold

7 does not hold

8 does not hold

9 Does not hold

10 Hold

Step-by-step explanation:

The detailed step by step verification is as shown in the attachment

4 0
3 years ago
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