Mathematics, 26.10.2019 04:43 emberferran

Astate end-of-grade exam in american history is a multiple-choice test that has 50 questions with 4 answer choices for each question. a student must get at least 25 correct to pass the test, and the questions are very difficult. question 1. if a student guesses on every question, what is the probability the student will pass? (round your answer to 4 decimal places). question 2. suppose, after studying, a student raises her chances of getting each question correct to 0.70. what is the probability that she will pass? (round your answer to 4 decimal places).

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Answer from: EthanIsHyper

Q1) The student has a 0.01% probability of passing the test.

Q2) She has a 99.91% probability of passing in the test.

Step-by-step explanation:

For each question, there are only two possible outcomes. Either he gets it correct, or he gets it wrong. So we solve this problem using the binomial probability distribution.

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:

Question 1.

There are 50 questions, so n = 50 .

The student is going to guess each question, so he has a $\pi = \frac{1}{4} = 0.25$ probability of getting it right.

He needs to get at least 25 question right.

So we need to find $P(X \geq 25)$ .

Using a binomial probability calculator, with n = 50 and $\pi = 0.25$ we get that $P(X \geq 25) = 0.0001$ .

This means that the student has a 0.01% probability of passing the test.

Question 2.

Now, we need to find $P(X \geq 25)$ with $\pi = 0.70$ . So $P(X \geq 25) = 0.9991$

She has a 99.91% probability of passing in the test.

Answer from: Quest

google dat sis

step-by-step explanation:

Answer from: Quest

answer:

total cost for tiles and paints is $924.

step-by-step explanation:

we have been given that a community hall is in the shape of a cuboid. the hall is 40m long 15m high and 3m wide.

the paint will be required for 4 walls and ceiling.

let us find area of walls and ceiling.

$\text{area of walls and ceiling}=(2*40*15)+(2*3*15)+(40*3)$

$\text{area of walls and ceiling}=1200+90+120$

$\text{area of walls and ceiling}=1410$

therefore, the area of walls and ceiling is 1410 square meters.

given: cost for 10 litre of paint is $10 and 10 litre paint covers 25 square meter. therefore,

$\text{ the total painting cost}=10*(\frac{1410}{25})$

$\text{ the total painting cost}=10*56.4=564$

therefore, the total painting cost is $564.

tiles will be required for floor. let us find the area of floor.

$\text{area of floor} = 40*3\text{ square meters}$

$\text{area of floor} =120\text{ square meters}$

given: 1m squared floor tiles costs $3. so,

$\text{total cost for tiles} = 3*120 = 360$

therefore, the total tiles cost is $360.

now let us find combined total cost of tiles and paint.

$\text{combined total cost}= 564+360 = 924$

therefore, the combined total cost of tiles and paint is $924.

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Astate end-of-grade exam in american history is a multiple-choice test that has 50 questions with 4...