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2 years ago

Can someone help me and explain? :')

Mathematics

1 answer:

sergij07 [2.7K]2 years ago

7 0

The square root of 11 = 3.3166
which is between 3 and 4 so the first one is the answer

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Find x 25 7 х I need help

Murljashka [212]

Answer:

24 = x

Step-by-step explanation:

You use Pythagorean theorem. Since the normal equation is $a^{2} + b^{2} =c^{2}$ , you already have the $c^{2}$ and another side which can be $a^{2}$ or $b^{2}$ .

Because you have the hypotenuse and a side , your equation looks like this now: $7^{2} +b^{2} = 25^{2}$

and when you solve for be you just subtract $25^{2} -7^{2}$ to get 24.

8 0

2 years ago

A test to detect an infection gives a positive result 98% of the time if a person is infected. It is 97% accurate for people who

sergeinik [125]

Consider this:

If a test gives a positive result for an infected person 98% of the time, that means that 2% of the time, it gives a negative result for an infected person, which would be a false negative.

Then,

if the test is 97& accurate (not precise) for non-infected people, that means that it gives a negative result 97& of the time. So a positive result will be given 3% of the time for non-infected people, which is considered a false positive.

5 0

3 years ago

Read 2 more answers

What should I buy? A study conducted by a research group in a recent year reported that of cell phone owners used their phones i

Llana [10]

Answer:

The probability that seven or more of them used their phones for guidance on purchasing decisions is 0.7886.

Step-by-step explanation:

The question is incomplete:

What should I buy? A study conducted by a research group in a recent year reported that 57% of cell phone owners used their phones inside a store for guidance on purchasing decisions. A sample of 14 cell phone owners is studied. Round the answers to at least four decimal places. What is the probability that seven or more of them used their phones for guidance on purchasing decisions?

We can model this as a binomial random variable, with p=0.57 and n=14.

$P(x=k)=\dbinom{n}{k} p^{k}q^{n-k}$

a) We have to calculate the probability that seven or more of them used their phones for guidance on purchasing decisions:

$P(x\geq7)=\sum_{k=7}^{14}P(x=k)\\\\\\$

$P(x=7)=\dbinom{14}{7} p^{7}q^{7}=3432*0.0195*0.0027=0.1824\\\\\\P(x=8) = \dbinom{14}{8} p^{8}q^{6}=3003*0.0111*0.0063=0.2115\\\\\\P(x=9) = \dbinom{14}{9} p^{9}q^{5}=2002*0.0064*0.0147=0.1869\\\\\\P(x=10) = \dbinom{14}{10} p^{10}q^{4}=1001*0.0036*0.0342=0.1239\\\\\\P(x=11) = \dbinom{14}{11} p^{11}q^{3}=364*0.0021*0.0795=0.0597\\\\\\P(x=12) = \dbinom{14}{12} p^{12}q^{2}=91*0.0012*0.1849=0.0198\\\\\\P(x=13) = \dbinom{14}{13} p^{13}q^{1}=14*0.0007*0.43=0.004\\\\\\$

$P(x=14) = \dbinom{14}{14} p^{14}q^{0}=1*0.0004*1=0.0004\\\\\\$

$P(x\geq7)=0.1824+0.2115+0.1869+0.1239+0.0597+0.0198+0.004+0.0004\\\\P(x\geq7)=0.7886$

7 0

3 years ago

An oil tank has to be drained for maintenance. The tank is shaped like a cylinder that is 5 ft long with a diameter of 1.8 ft .

dangina [55]

$\bf \textit{volume of a cylinder}\\\\
V=\pi r^2 h\qquad 
\begin{cases}
r=radius=\frac{diameter}{2}\\
h=height\\
----------\\
diameter=1.8\\
r=\frac{1.8}{2}=0.9\\
h=5
\end{cases}\implies V=\pi \cdot 0.9^2\cdot 5\\\\
-------------------------------\\\\
\textit{is draining at }\boxed{2.1}\ \frac{ft^3}{min}\textit{ , it has a total of }\boxed{\pi \cdot 0.9^2\cdot 5} \ ft^3
\\\\\\
\textit{it'll take }\cfrac{\pi \cdot 0.9^2\cdot 5}{2.1}\ minutes$

3 0

3 years ago

PLEASE HELP ME IM BEGGING YOU!!! FIND THE VALUE OF X

Korvikt [17]

84 I'm sure it's that I did it before

8 0

3 years ago

Read 2 more answers