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2 years ago

Mrs. Sparks is a 9th-grade Algebra 1 teacher. She teaches three

Mathematics

1 answer:

soldi70 [24.7K]2 years ago

7 0

Answer:

Imagine that scientists have just discovered a non-bird dinosaur skeleton. They want to know whether the dinosaur was closely related to birds. What features in ...

Step-by-step explanation:

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Jane must get at least three of the four problems on the exam correct to get an A. She has been able to do 80% of the problems o

NISA [10]

Answer:

a) There is n 81.92% probability that she gets an A.

b) If she gets the first problem correct, there is an 89.6% probability that she gets an A.

Step-by-step explanation:

For each question, there are only two possible outcomes. Either the answer is correct, or it is not. This means that we can solve this problem using binomial distribution probability concepts.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}$

In which $C_{n,x}$ is the number of different combinatios of x objects from a set of n elements, given by the following formula.

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

And $\pi$ is the probability of X happening.

For this problem, we have that:

The probability she gets any problem correct is 0.8, so $\pi = 0.8$ .

(a) What is the probability she gets an A?

There are four problems, so $n = 4$

Jane must get at least three of the four problems on the exam correct to get an A.

So, we need to find $P(X \geq 3)$

$P(X \geq 3) = P(X = 3) + P(X = 4)$

$P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}$

$P(X = 3) = C_{4,3}.(0.80)^{3}.(0.2)^{1} = 0.4096$

$P(X = 4) = C_{4,4}.(0.80)^{4}.(0.2)^{0} = 0.4096$

$P(X \geq 3) = P(X = 3) + P(X = 4) = 2*0.4096 = 0.8192$

There is n 81.92% probability that she gets an A.

(b) If she gets the first problem correct, what is the probability she gets an A?

Now, there are only 3 problems left, so $n = 3$

To get an A, she must get at least 2 of them right, since one(the first one) she has already got it correct.

So, we need to find $P(X \geq 2)$

$P(X \geq 3) = P(X = 2) + P(X = 3)$

$P(X = 2) = C_{3,2}.(0.80)^{2}.(0.2)^{1} = 0.384$

$P(X = 4) = C_{3,3}.(0.80)^{3}.(0.2)^{0} = 0.512$

$P(X \geq 3) = P(X = 2) + P(X = 3) = 0.384 + 0.512 = 0.896$

If she gets the first problem correct, there is an 89.6% probability that she gets an A.

3 0

3 years ago

What is the equation of the line written in general form (2,4) (-1,-5)

elena-s [515]

First, you must find the slope, which is -5-4/-1-4, or 1.8, and then put it in point-slope form, or y-4=1.8(x-2), which simplifies to y-4=1.8x-3.6, and so put it in general/standard form, you have to subtract 1.8x from both sides and then add 4 to both sides, and lastly divide both sides of the equation by -1.8 to get x+y=1.889, or x+y=1.6/1.8. This is not copied and pasted.

6 0

2 years ago

What is the equivalent decimal? Drag the answer into the box to match the fraction. 6/11

Naya [18.7K]

Answer:

The answer is D

Step-by-step explanation:

5 0

2 years ago

Read 2 more answers

Help.. please... my due is in 5 minutes

Diano4ka-milaya [45]

<h3>Answer:</h3>

y = x - 5

<h3>Step-by-step explanation:</h3>

If 5 is being subtracted from x, then it would look like x-5.

Since x-5 represents 5 being subtracted from x, y=x-5 is the correct answer because the other options aren't representing 5 subtracted from x.

3 0

2 years ago

A bag contains 11 tiles, one for each of the letters in the word BLUEBERRIES. You randomly choose a tile.

wel

2/11

there’s 2 R’s and 11 total so

possible outcomes/ overall outcomes

7 0

2 years ago