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3 years ago

A bacteria culture begins with 4 bacteria which double in size every hour. How many bacteria exist in the culture after 8 hours.

Mathematics

1 answer:

ale4655 [162]3 years ago

6 0

Answer:

1024

Step-by-step explanation:

There are 4 bacteria at the start. We can make an equation to represent the phenomena explained in the question.

As it is written in the question that the bacteria culture doubles in every hour.

So,

Let t represent the unit of time

So the number of bacteria after t unit of time will be

Number of bacteria after t unit of time=4*2^t

We have to calculate number of bacteria after 8 hours, so t = 8

Number of bacteria after 8 hours=4*2^8

=4*256

=1024

So the bacteria after 8 hours in the culture will be 1024..

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Find the probability that a randomly generated bit string of length 10 does not contain a 0 if bits are independent and if:a) a

lara31 [8.8K]

Answer:

A) 0.0009765625

B) 0.0060466176

C) 2.7756 x 10^(-17)

Step-by-step explanation:

A) This problem follows a binomial distribution. The number of successes among a fixed number of trials is; n = 10

If a 0 bit and 1 bit are equally likely, then the probability to select in 1 bit is; p = 1/2 = 0.5

Now the definition of binomial probability is given by;

P(K = x) = C(n, k)•p^(k)•(1 - p)^(n - k)

Now, we want the definition of this probability at k = 10.

Thus;

P(x = 10) = C(10,10)•0.5^(10)•(1 - 0.5)^(10 - 10)

P(x = 10) = 0.0009765625

B) here we are given that p = 0.6 while n remains 10 and k = 10

Thus;

P(x = 10) = C(10,10)•0.6^(10)•(1 - 0.6)^(10 - 10)

P(x=10) = 0.0060466176

C) we are given that;

P((x_i) = 1) = 1/(2^(i))

Where i = 1,2,3.....,n

Now, the probability for the different bits is independent, so we can use multiplication rule for independent events which gives;

P(x = 10) = P((x_1) = 1)•P((x_2) = 1)•P((x_3) = 1)••P((x_4) = 1)•P((x_5) = 1)•P((x_6) = 1)•P((x_7) = 1)•P((x_8) = 1)•P((x_9) = 1)•P((x_10) = 1)

This gives;

P(x = 10) = [1/(2^(1))]•[1/(2^(2))]•[1/(2^(3))]•[1/(2^(4))]....•[1/(2^(10))]

This gives;

P(x = 10) = [1/(2^(55))]

P(x = 10) = 2.7756 x 10^(-17)

3 0

3 years ago

Two cooling fans are installed in some laptop computers. Suppose the reliability of each cooling fan is 0.92. What percent impro

wlad13 [49]

Answer:

Step-by-step explanation:

Given that:

Reliability of each = 0.92

r = 0.92

1 - (1 - r)(1 - r) = 1 - (0.08)(0.08) = 1 - 0.0064 = 0.9936

Percentage improvement :

1 - (0.9936) / r

1 - (0.9936 / 0.92)

1 - 1.08

= - 0.08

= 0.08 / 100 = 8%

5 0

3 years ago

For 0 ≤ ϴ < 2π, how many solutions are there to tan(StartFraction theta Over 2 EndFraction) = sin(ϴ)? Note: Do not include va

Black_prince [1.1K]

Answer:

3 solutions:

$\theta={0, \frac{\pi}{2}, \frac{3\pi}{2}}$

Step-by-step explanation:

So, first of all, we need to figure the angles that cannot be included in our answers out. The only function in the equation that isn't defined for some angles is $tan(\frac{\theta}{2})$ so let's focus on that part of the equation first.

We know that:

$tan(\frac{\theta}{2})=\frac{sin(\frac{\theta}{2})}{cos(\frac{\theta}{2})}$

therefore:

$cos(\frac{\theta}{2})\neq0$

so we need to find the angles that will make the cos function equal to zero. So we get:

$cos(\frac{\theta}{2})=0$

$\frac{\theta}{2}=cos^{-1}(0)$

$\frac{\theta}{2}=\frac{\pi}{2}+\pi n$

$\theta=\pi+2\pi n$

we can now start plugging values in for n:

$\theta=\pi+2\pi (0)=\pi$

if we plugged any value greater than 0, we would end up with an angle that is greater than $2\pi$ so, that's the only angle we cannot include in our answer set, so:

$\theta\neq \pi$

having said this, we can now start solving the equation:

$tan(\frac{\theta}{2})=sin(\theta)$

we can start solving this equation by using the half angle formula, such a formula tells us the following:

$tan(\frac{\theta}{2})=\frac{1-cos(\theta)}{sin(\theta)}$

so we can substitute it into our equation:

$\frac{1-cos(\theta)}{sin(\theta)}=sin(\theta)$

we can now multiply both sides of the equation by $sin(\theta)$

so we get:

$1-cos(\theta)=sin^{2}(\theta)$

we can use the pythagorean identity to rewrite $sin^{2}(\theta)$ in terms of cos:

$sin^{2}(\theta)=1-cos^{2}(\theta)$

so we get:

$1-cos(\theta)=1-cos^{2}(\theta)$

we can subtract a 1 from both sides of the equation so we end up with:

$-cos(\theta)=-cos^{2}(\theta)$

and we can now add $cos^{2}(\theta)$

to both sides of the equation so we get:

$cos^{2}(\theta)-cos(\theta)=0$

and we can solve this equation by factoring. We can factor $cos(\theta)$ to get:

$cos(\theta)(cos(\theta)-1)=0$

and we can use the zero product property to solve this, so we get two equations:

Equation 1:

$cos(\theta)=0$

$\theta=cos^{-1}(0)$

$\theta={\frac{\pi}{2}, \frac{3\pi}{2}}$

Equation 2:

$cos(\theta)-1=0$

we add a 1 to both sides of the equation so we get:

$cos(\theta)=1$

$\theta=cos^{-1}(1)$

$\theta=0$

so we end up with three answers to this equation:

$\theta={0, \frac{\pi}{2}, \frac{3\pi}{2}}$

7 0

2 years ago

45% of the population of a city are men

leonid [27]

Answer:

$\boxed{\textsf{ The number of children is \textbf{24150}.}}$

Step-by-step explanation:

Given that the 45% of the population of a city are men and 15% are children . The number of women is 64,400 . And we need to find the number of children . Here ,

$\sf\implies Percentage_{(men)}= 45/% .\\\\\sf\implies Percentage_{(children)}= 15\% .$

So the percentage of women will be equal to [ 100 - ( 45 -15) ]% = [ 100 - 60 ]% = 40% .

So let us take the total number of people be x . So ,

$\purple{\bigstar}\underline{\underline{\boldsymbol{ According\ to \ Question :- }}}$

$\sf\implies 40\% \ of \ x \ = \ 64,400 \\\\\sf\implies \dfrac{40x}{100}= 64,400 \\\\\sf\implies x =\dfrac{64,400\times 100}{40}\\\\\sf\implies \boxed{\pink{\sf x = 161,000 }}$

$\rule{200}2$

The percentage of children = 15% :-

$\sf\implies Number_{(children)}= 15\% \ of 161,000\\\\\sf\implies Number_{(children)}= \dfrac{15}{100}\times 161,000 \\\\\sf\implies \boxed{\pink{\frak {Number_{(children)}= 24150 }}}$

5 0

3 years ago

Mike travels 13 miles per 2 hours on his bike.

LiRa [457]

Answer:

It took Markus half an hour to drive home from work. He averaged 34 miles per hour. How far does Markus live from his work?

Solution

We are given that it takes 1/2 an hour for the trip. This is a time:

t = 1/2

We are given that he averages 34 miles per hour. This is a rate:

r = 34

We are asked how few he has traveled. This is a distance. We use the d=rt equation:

d = rt

= (34)(1/2)

= 17

Markus lives 17 miles from work.

Now try one by yourself. If you want to see the answer, put your mouse on the yellow rectangle and the answer will appear.

Exercise 1

The current along the beach is moving towards the south at 1.5 miles per hour. If a piece of debris is placed into the water, how far will the current take it in 6 hours?

Step-by-step explanation:

4 0

3 years ago