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2 years ago

When figuring out the amount of mulch would be needed for Alex's back yard, he created an equation that

Mathematics

1 answer:

soldier1979 [14.2K]2 years ago

7 0

Answer:

Alex will need 14 bags

Step-by-step explanation:

B= 4(2x+7)+3(2x+7)

and

2x+7=2

First, we should solve the second equation to obtain x:

2x+7=2

2x=2-7

x= -5/2

Then, we use this answer to calculate B:

B=4(2(-5/2)+7)+3(2)

B=4(-5+7)+6

B=4(2)+6

B=8+6

B=14

Alex will need 14 bags

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You can divide the two values A = diameter of bacterium B = diameter of virus A/B = (10^(-6))/(10^(-7)) A/B = 10^(-6-(-7)) A/B = 10^(-6+7) A/B = 10^(1) A/B = 10 Since the ratio of the two diameters is 10, this means that the diameter of the bacterium is 10 times greater than that of the virus.

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2 years ago

According to a study conducted by the Toronto-based social media analytics firm Sysomos, 71% of all tweets get no reaction. That

timama [110]

Answer:

Let X the random variable of interest "number of tweets with no reaction", on this case we now that:

$X \sim Binom(n=100, p=0.71)$

And the expected value is given by:

$E(X) = np =100*0.71 = 71$

So we expect about 71 tweets with no reaction for this case.

Step-by-step explanation:

Previous concepts

A Bernoulli trial is "a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is conducted". And this experiment is a particular case of the binomial experiment.

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Solution to the problem

Let X the random variable of interest "number of tweets with no reaction", on this case we now that:

$X \sim Binom(n=100, p=0.71)$

And the expected value is given by:

$E(X) = np =100*0.71 = 71$

So we expect about 71 tweets with no reaction for this case.

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2 years ago

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Answer:Perry and Lorna take the maximum time and Maria and Lorna take the minimum time when they work together.

Explanation: Since, according to the question- Perry takes time when he works alone = 3 hours

Similarly, Maria takes = 2 hours, While Lorna takes= 2 hours 30 minutes or 2.5 hours.

since, there are three people thus their are three possibility to choose any two of them.

1- when Perry and Maria work together then time taken by them is $\frac{1}{1/2+1/3}$ = $\frac{1}{5/6}$ = 6/5= 1 hour 12 minutes.

2- when Maria and Lorna work together then time taken by them is $\frac{1}{1/2 + 1/2.5}$ = 10/9= 1 hours 1/9 minutes ≈ 1 hours 7 min

3- when Perry and Lorna work together then time taken= $\frac{1}{1/3+1/2.5}$ = 15/11= 1 hour 4/11 minutes≈ 1 hours 21 minutes

From the above explanation, it has been proved that when we talk about 2 members team then Perry and Lorna take the maximum time. While Maria and Lorna take the minimum time when they work together.

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2 years ago

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since 20" is longer than 17.2 it can't be a rectangle

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