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luda_lava [24]
3 years ago
12

In a lab experiment, 720 bacteria are placed in a Petri dish. The conditions are such that the number of bacteria is able to dou

ble every 26 hours. How long would it be, to the nearest 10th of an hour until there are 1310 bacteria present?
Mathematics
1 answer:
MakcuM [25]3 years ago
6 0

Answer:

22.4 hours

Step-by-step explanation:

The population of bacteria is modelled by the equation:

P=P_0e^{rt}

From the the question, the initial population of bacteria is 720.

So after 26 hours, we have:

P=2P_0

This implies that:

2P_0=P_0e^{26r}

2=e^{26r}

26r =  ln(2)

r =  \frac{ ln(2) }{26}

r = 0.0267

We want to find how long it will take for there to be 1310 bacteria present.

1310=720e^{0.0267t}

\frac{1310}{720}  =  {e}^{0.0267t}

\ln(\frac{1310}{720})  = {0.0267t}

0.59853= {0.0267t}  \\ t =  \frac{0.59853}{0.0267}

t = 22.417

To the nearest tenth , it will take 22.4 hours

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state whether each expression is meaningful. if not, explain why. if so, state whether it is a vector or a scalar.
DanielleElmas [232]

The dot product of two vectors gives scalar quantity and between scalar quantity, we can not apply any product so options (b), (d), and (e) are not meaningful.

<h3>What is a vector?</h3>

An item with both magnitude and direction is referred to be a vector.

A vector can be visualized geometrically as a straight spline, with a pointing in the orientation and a length equal to the value of the vector.

A line with an arrow in its direction can also be used to represent a vector, and the length of the line relates to the vector's amplitude.

The dot product of two vectors gives scalar quantity while the cross product gives a vector quantity.

Now,

In option (B) ;

a Х (b . c) now here b . c is a scalar quantity and we can not cross multiply a scalar with a vector.

In option (D) ;

(a.b) Χ (c.d) where we cannot multiply two scalars by cross product.

In option (E);

a.(b.c) we can not multiply two scalars by the dot product.

Hence "The dot product of two vectors gives scalar quantity and between scalar quantity, we can not apply any product".

For more information about vector,

brainly.com/question/13322477

#SPJ4

The given question has a missing option which is given below,

8 0
2 years ago
To test μ for an x distribution that is mound-shaped using sample size n ≥ 30, how do you decide whether to use the normal or st
Luden [163]
Answer:
Use the normal distribution if the population standard deviation is known.
Use the student's t distribution when the population standard deviation is unknown.

Explanation:
A mound-shaped distribution refers to the normal distribution.
A good sample size for testing against the normal distribution should be
n >= 30.
The condition for the sample size is satisfied.
However, we are not given the population standard deviation, therefore it is assumed to be unknown.
Therefore the student's t distribution should be used. 
6 0
3 years ago
The ratio of boys to girl in a school is 5:7 if there are 600 students, how many girls are there
larisa86 [58]

Answer:

350 girls

Step-by-step explanation:

So,

The secret to solving problems with ratios is to find the value of one unit.

5:7 = 12 units total

To find one unit, divide the total number of students by the total number of units.

600/12 = a

Simplify

50/1 = a

50 = a

The value of each unit is 50.

Now, multiply the units by the numbers in the ratio.

50(5) = b

250 = boys

50(7) = x

350 = x

There are 350 girls.

3 0
2 years ago
If a line goes through the point (8,9) and has a slope of negative 3/4 what is the starting value?
scZoUnD [109]

I assume by starting value, you mean y-intercept. The y-intercept is 15

To find this, we need to use slope intercept form and the given information to find it.

y = mx + b ----> plug in the known values

9 = -3/4(8) + b

9 = -6 + b

15 = b

Therefore, the starting value is 15.

5 0
3 years ago
Mathematics help quickly if its wrong ill get beat
Anuta_ua [19.1K]

Answer:

FIRST OPTION

Step-by-step explanation:

its the first option since the birds like the red bugs more all the red bugs will get eaten and the green ones will survive and evolve

5 0
3 years ago
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