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2 years ago

5

How many questions would I have to miss on a 25 question test to get 88% ?

1 answer:

N76 [4]2 years ago

7 0

Let's start with the question, how many questions do you need to get 88%?

so were are looking for
?/25 = 88% and 88% is also 0.88 so we can multiply 25 by 0.88

we get 22

But this doesn't here. the question asks us how many mistakes do you need. you can just subtract 22 from 25

25-22= 3
you need 3 misses to get 88%

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A student takes an exam containing 1414 multiple choice questions. The probability of choosing a correct answer by knowledgeable

Readme [11.4K]

Answer:

0.0082 = 0.82% probability that he will pass

Step-by-step explanation:

For each question, there are only two possible outcomes. Either the students guesses the correct answer, or he guesses the wrong answer. The probability of guessing the correct answer for a question is independent of other questions. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

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

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

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

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

And p is the probability of X happening.

In this problem we have that:

$n = 14, p = 0.3$ .

If the student makes knowledgeable guesses, what is the probability that he will pass?

He needs to guess at least 9 answers correctly. So

$P(X \geq 9) = P(X = 9) + P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14)$

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

$P(X = 9) = C_{14,9}.(0.3)^{9}.(0.7)^{5} = 0.0066$

$P(X = 10) = C_{14,10}.(0.3)^{10}.(0.7)^{4} = 0.0014$

$P(X = 11) = C_{14,11}.(0.3)^{11}.(0.7)^{3} = 0.0002$

$P(X = 12) = C_{14,12}.(0.3)^{12}.(0.7)^{2} = 0.000024$

$P(X = 13) = C_{14,13}.(0.3)^{13}.(0.7)^{1} = 0.000002$

$P(X = 14) = C_{14,14}.(0.3)^{14}.(0.7)^{0} \cong 0$

$P(X \geq 9) = P(X = 9) + P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) = 0.0066 + 0.0014 + 0.0002 + 0.000024 + 0.000002 = 0.0082$

0.0082 = 0.82% probability that he will pass

6 0

2 years ago

If f(x)=sinx−1/cos2x, then limx→π2f(x) is equivalent to which of the following?

Harrizon [31]

Answer:

2

Step-by-step explanation:

Given g(x) = sin(x)-1/cos2(x), we are to find the limit if the function g(x) as g(x) tends to π/2

Substituting π/2 into the function

lim x-->π/2 sin(x)-1/cos 2(x)

= sin(π/2) - 1/cos(2)(π/2)

= 1 - 1/cosπ

= 1- 1/-1

= 1 -(-1)

= 1+1

= 2

Hence the limit of the function h(x) = sin(x)-1/cos2(x) as x--> π/2 is 2

8 0

3 years ago

2.952 + 39.24 = <br>A: 42.192<br>B: 68.76<br>C: 6.876<br>D: 687.6<br>E: 36.288<br>F: 42.76

kirill [66]

Answer:

The answer to this question is A

4 0

3 years ago

Read 2 more answers

If x to the power of 2 equals 196 what does x equal

natulia [17]

Answer:

14

Step-by-step explanation:

<h2><u>Solve for x</u></h2>

<u /> $x^{2} = 196$

this can be solved by square rooting 196

$x = \sqrt{196}$

x = 14

<h3><u>the value for x is 14</u></h3>

3 0

2 years ago

Read 2 more answers

It says use cofunction but still i didnt understand

torisob [31]

Answer:

- $\frac{\pi }{22\\}$

Step-by-step explanation:

$\frac{5\pi }{11}$ -pi/2

5 0

3 years ago