QUESTION 9

Mathematics

2 answers:

yanalaym [24]3 years ago

5 0

Answer:

Step-by-step explanation:

Lorico [155]3 years ago

4 0

Joe drank drinks all day long and not enough info

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What is this expression equivilante to?

Andru [333]

Answer:

$-13x^{2}$ +34x-29

Step-by-step explanation:

7 0

3 years ago

7-4i divided by <br> 2+i <br> how to solve it?

cupoosta [38]

$\cfrac{7-4i}{2+i}\\\\ = \cfrac{(7-4i)(2-i)}{(2+i)(2-i)} \\\\ =\cfrac{14-7i-8i-4}{4+1} \\\\= \cfrac{10-15i}{5} \\\\= \cfrac{5(2-3i)}{5} \\\\=2-3i$

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4 years ago

A lot of 25 skylight covers are received at your construction site, and before installation are subjected to an acceptance testi

8090 [49]

Answer:

If the lot has 4 defective covers out of 25 total covers, the probability of accepting the lot is P=0.98.

Step-by-step explanation:

We have a population of N=25 skylight covers, were K=4 are defective.

We sample n=5 covers, and we will accept the lot if k=2 or fewer are defective.

We will use the hypergeometric distribution to model this probabilities.

First, to be accepted, the sample can have 2, 1 or 0 defective covers, so the probability of being accepted is:

$P(accepted)=P(k\leq2)=P(k=0)+P(k=1)+P(k=2)$

The probability that there are k defective covers in the sample is:

$P(k)=\dfrac{\dbinom{k}{k}\dbinom{N-k}{n-k}}{\dbinom{N}{n}}$

Then, we can calculate the individual probabilities as:

$P(k=0)=\dfrac{\dbinom{4}{0}\cdot \dbinom{25-4}{5-0}}{\dbinom{25}{5}}=\dfrac{\dbinom{4}{0}\cdot \dbinom{21}{5}}{\dbinom{25}{5}}\\\\\\P(k=0)=\dfrac{1\cdot 20349}{53130}=0.38$

$P(k=1)=\dfrac{\dbinom{4}{1}\cdot \dbinom{25-4}{5-1}}{\dbinom{25}{5}}=\dfrac{\dbinom{4}{1}\cdot \dbinom{21}{4}}{\dbinom{25}{5}}\\\\\\P(k=1)=\dfrac{4\cdot 5985}{53130}=0.45$

$P(k=2)=\dfrac{\dbinom{4}{2}\cdot \dbinom{25-4}{5-2}}{\dbinom{25}{5}}=\dfrac{\dbinom{4}{2}\cdot \dbinom{21}{3}}{\dbinom{25}{5}}\\\\\\P(k=2)=\dfrac{6\cdot 1330}{53130}=0.15$