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3 years ago

Event A occurs with probability 0.2. Event B occurs with probability 0.8. If A and B are disjoint (mutually exclusive), then

Mathematics

2 answers:

larisa86 [58]3 years ago

6 0

Answer:

Step-by-step explanation:

If A and B are disjoint events, then P(A∩B) = 0 (because A and B haven't common parts), intersection ∩ can be also denoted with "and", so P(A and B) =0.

On the other hand, if A and B are disjoint events, then P(AUB) = P(A)+P(B). Union U can be also denoted with "or", then P(A or B) = P(A)+P(B).

P(A or B)= 0.2+0.8 = 1.

So, the answer is B.

swat323 years ago

4 0

What's the question? Do you want to prove these statements?

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A cone-shaped pile of sawdust has a base diameter of 38 feet, and is 14 feet tall. Find the volume of the pile

Romashka-Z-Leto [24]

Answer:

Given: Diameter of cone = 38 feet and height of cone = 14 feet.

Volume of cone V with radius r is one-third the area of the base B times the height h.

i,e $V = \frac{1}{3} B \cdot h$ = $\frac{1}{3} \pi r^2h$ ......[1]

,where B = $\pi r^2$

First find the radius(r);

Using Diameter(D) = 2r

38 =2r

Divide both side by 2 we get;

$\frac{38}{2} =\frac{2r}{2}$

Simplify:

19 = r

or r =19 feet

Now, substitute the value of r = 19 feet and h = 14 feet in [1] [ Use value of $\pi = \frac{22}{7}$ ]

then, we have:

$V = \frac{1}{3} \pi r^2h = \frac{1}{3} \cdot \frac{22}{7} \cdot (19)^2 \cdot (14)$

V = $=\frac{1}{3}\cdot 22 \cdot 19 \cdot 19 \cdot 2 = \frac{22 \cdot 19 \cdot 19 \cdot 2}{3}$

V = $\frac{15884}{3} =5,294.66667$ ≈ 5,294.67 cubic feet.

therefore, the volume of pile is; ≈ 5,294.67 cubic feet.

4 0

3 years ago

True or false? If you took a true "if-then" statement and reversed the clauses, the new statement would also be true.

Hatshy [7]

Reversing the clauses of an "if-then" statement only sometimes makes the new statement true, so it isn't true or false. For example, reversing the clauses of "if 1=x, then x=1" makes the new statement true, but reversing the clauses of "if x=2, then |x|=2" doesn't.

8 0

3 years ago

ccording to the U.S. National Weather Service, at any given moment of any day, approximately 1000 thunderstorms are occurring wo

viva [34]

Answer:

The critical value of z for 99% confidence interval is 2.5760.

The 99% confidence interval for population mean number of lightning strike is (7.83 mn, 8.37 mn).

Step-by-step explanation:

Let X = number of lightning strikes on each day.

A random sample of n = 23 days is selected to observe the number of lightning strikes on each day.

The random variable X has a sample mean of, $\bar x=8.1\ mn$ and the population standard deviation, $\sigma=0.51\ mn$ .

The (1 - α)% confidence interval for population mean μ is:

$CI=\bar x\pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$

Compute the critical value of z for 99% confidence interval is:

$z_{\alpha/2}=z_{0.01/2}=z_{0.005}=2.5760$

*Use a z-table.

The critical value of z for 99% confidence interval is 2.5760.

Compute the 99% confidence interval for population mean number of lightning strike as follows:

$CI=\bar x\pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}\\=8.1\pm2.5760\times\frac{0.51}{\sqrt{23}}\\=8.1\pm0.2738\\=(7.8262, 8.3738)\\\approx(7.83, 8.37)$

Thus, the 99% confidence interval for population mean number of lightning strike is (7.83 mn, 8.37 mn).

The 99% confidence interval for population mean number of lightning strike implies that the true mean number of lightning strikes lies in the interval (7.83 mn, 8.37 mn) with 0.99 probability.

3 0

3 years ago

al atardecer un árbol proyecta una sombra de 2,5 m de longitud. Si la distancia desde la parte más alta del árbol al extremo más

frez [133]

Answer:

no copies o lo busques el link que te mando porque tiene virus ok

3 0

2 years ago

Sierra left $4.50 as a tip for a waiter. THis was 18% of the bull before the tip, How much was her total bill before the tip?

andreyandreev [35.5K]

let's say the bill without the tip is "x" amount, so that'd be the 100% of the bill, but we also know that 4.50 is the 18% of "x".

so if 4.50 is the 18% of "x", how much is "x"?

$\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 4.50&18\\ x&100 \end{array}\implies \cfrac{4.5}{x}=\cfrac{18}{100}\implies 450=18x \\\\\\ \cfrac{450}{18}=x\implies 25=x$

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3 years ago