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adoni [48]
2 years ago
9

8. At the beginning of the semester, a professor tells students that if they study for the tests, then there is a 55% chance the

y will get a B or higher on the tests. If they do not study, there is a 20% chance that they will get a B or higher on the tests. The professor knows from prior surveys that 60% of students study for the tests. The probabilities are displayed in the tree diagram.
The professor informs the class that there will be a test next week. What is the probability that a randomly selected student studied for the test if they pass it with a B or higher?
A. 0.20
B. 0.55
C. 0.60
D. 0.80

Mathematics
1 answer:
Bezzdna [24]2 years ago
3 0

Answer:

.8

Step-by-step explanation:

S= studies for

B= score of b or higher

we want P(S|B)

Using Bayes' theorem we can solve for the probability

S|B=\frac{B|S*S}{B|S*S+B|S'*S'}=\frac{.55*.6}{.55*.6+.2*.4}=0.80487804878

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Can someone help me with this? Please this would mean so much.
Paha777 [63]

Answers:

x = angle MLN = 35 degrees

angle FLJ = 55 degrees

=================================================

Explanation:

This problem is fairly tricky if you're not sure what to look for. A slight clue is that they've marked a red point that strangely doesn't have a label on it. It's a fairly small point but it's definitely there if you look closely. While this point's location isn't exactly what we want, we're fairly close. Start at point L and draw a ray through the center point P. Ray LP will intersect the circle at point A, as shown in the diagram below.

From here, draw segments FA and MA. Now notice that inscribed angle LMF = 55 and inscribed angle FAL both subtend the same arc. The term "subtend" basically means "cut off". This arc that the inscribed angles subtend is minor arc FL. A minor arc is where you travel the shorter path around the circle, which indicates its measure is less than 180 degrees.

Since inscribed angles LMF and FAL subtend the same minor arc, this makes the inscribed angles to be congruent.

In short: angle FAL is 55 degrees

----------------------

Segment LA goes through the center P. Through Thales theorem, we know that inscribed angle LFA is 90 degrees. Consequently, we can determine that inscribed angle FLA is 90-55 = 35 degrees.

Segment JL is tangent to the circle, meaning that angle ALJ is 90 degrees. So angle FLJ is 90-35 = 55 degrees.

It's not a coincidence that angle FLJ, angle FAL, and angle LMF are the same measure.

----------------------

We found that angle FAL was 55 degrees. Applying Thales theorem again shows that angle MAF is 90 degrees. Therefore, angle LAM is 90-55 = 35 degrees.

Focus now on triangle LMA. This is also a right triangle (Thales Theorem). The upper acute angle we found was angle LAM = 35, so the lower acute angle is ALM = 55.

Then we can find angle MLN = (angle ALN) - (angle ALM) = 90 - 55 = 35

In short, angle MLN = 35 degrees

Similar to the previous section, it is not a coincidence that angles LFM, LAM and MLN are the same measure.

------------------------

As an alternative, since we know angle FLJ = 55, and angle FLM is 90 degrees, this means...

(angle FLJ)+(angle FLM) + (angle MLN) = 180

55 + 90 + angle MLN = 180

145 + angle MLN = 180

angle MLN = 180 - 145

angle MLN = 35 degrees

7 0
2 years ago
In oak valley the cost of gas averaged $3.50 per gallon qt the start of April the rose 6% during April and dropped 10% during Ma
andreev551 [17]

Answer:

$ 3.34

Step-by-step explanation:

3.50 * 1.06    cost at end of April    then find 90% of this to find end of May

3.50 * 1.06    * .9 = $ 3.34

8 0
2 years ago
I need help badly please with number 2 ...help me .. please no links or I will report you
klasskru [66]

9514 1404 393

Answer:

  $62.74

Step-by-step explanation:

The annuity formula can be used to find the payment needed. Fill in the known values and solve for the unknown.

The future balance due to a series of payments is given by ...

  A = P(n/r)((1 +r/n)^(nt) -1)

where A is the account balance P is the payment made each period, n is the number of periods per year, r is the annual interest rate, and t is the number of years.

You have A = $20,000, r = 0.041, n = 12, t = 18 and you want to find P

  P = A(r/n)/((1 +r/n)^(nt) -1)

  P = $20,000(0.041/12)/((1 +0.041/12)^(12·18) -1) ≈ $62.74

A monthly payment of $62.74 is required.

4 0
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Simplify the expression.<br><br> −10−3
kirill115 [55]

Answer:

-13

Step-by-step explanation:

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BigorU [14]
I think it would D) E = 6 + s
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