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Paul [167]
3 years ago
9

A sample of bacteria is decaying according to a half-life model. If the sample begins with 800 bacteria, and after 13 minutes th

ere are 320 bacteria, after how many minutes will there be 15 bacteria remaining? Round your answer to the nearest whole number.
Mathematics
1 answer:
nikklg [1K]3 years ago
3 0

Answer:

56.42 minutes

Step-by-step explanation:

The initial sample= y0 = 800

After 13 minutes , amount = 320

Y= y0e-kt

320 = 800e-k(13)

320/800 = e-k13

0.4 = e-k13

In0.4 = -k13

-0.91629= -k13

0.07048= k

Y = 800e-0.07048t

Minutes when the bacterial present will be 15

15 = 800e-0.07048t

15/800= e-0.07048t

0.01875 = e-0.07048t

In 0.01875 = -0.07048t

-3.97656 = -0.07048t

-3.97656/-0.07048= t

56.42 = t

56.42 minutes

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39 is what percent of 96
ra1l [238]

Answer:

40.625%

Step-by-step explanation:

This is a very simple question.

We have to understand converting word equations to algebraic ones.

"is" means "="

"of" means "*"

So, we can write:

39 = what percent * 96

Now, we let "what percent" be "p" and solve the equation for p:

39 = P * 96

So,

39 = P * 96\\39=96P\\P=\frac{39}{96}\\P=0.40625

Converting this decimal to percentage means multiplying by 100, so we have:

0.40625 * 100

= 40.625%

7 0
4 years ago
How to name a ray 3 different ways?
MAVERICK [17]
<span>1)A ray has one endpoint and extends indefinitely in one direction.
2)A pair of opposite rays are two rays that have the same endpoint and extend in opposite directions.
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5 0
4 years ago
Solve (16×^3-3×^2+43×-5)÷(×^2-2)
Oksana_A [137]

Answer:

3872/(x^2 - 2)

Step-by-step explanation:

Simplify the following:

(16^3 - 3^2 - 5×43)/(x^2 - 2)

3^2 = 9:

(16^3 - 9 - 5×43)/(x^2 - 2)

16^3 = 16×16^2:

(16×16^2 - 9 - 5×43)/(x^2 - 2)

| 1 | 6

× | 1 | 6

| 9 | 6

1 | 6 | 0

2 | 5 | 6:

(16×256 - 9 - 5×43)/(x^2 - 2)

16×256 = 4096:

(4096 - 9 - 5×43)/(x^2 - 2)

43 (-5) = -215:

(4096 - 9 + -215)/(x^2 - 2)

4096 - 9 - 215 = 3872:

Answer: 3872/(x^2 - 2)

7 0
3 years ago
2y + 9 = 4 pls aswer the question pls pls​
Aleonysh [2.5K]

Step-by-step explanation:

2y+9= 4

2y=-5

y=-5/2

y= -2and 1/2

3 0
2 years ago
The toy shop stocks tricycles and go-carts.
Mandarinka [93]

Total number of wheels in the toy shop = 37 wheels

Number of wheels for tricycles = 3

Number of wheels for go-carts = 5

  • Since the total number of tricycles and go-carts are not given, we solve this question using Assumption.

  • Let's assume: We have 4 tricycles and 4 go-carts

(4 x 3) + (4 x 5)

= 12 + 20

= 32 wheels. This assumption is wrong.

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(4 x 3) + (5 x 5)

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= 37 wheels. This assumption is correct.

Therefore, we have  4 tricycles and 5 go-carts in the toy shop.

To learn more, visit the link below:

brainly.com/question/23264573

3 0
3 years ago
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