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3 years ago

Please help with this question! (Brainliest)

Mathematics

2 answers:

insens350 [35]3 years ago

6 0

Answer:

Step-by-step explanation:

$- 9 \: \: . \: \: (5j + k) \\ - 9(5j) -9(k) \\ - 45j - 9k \\$

Korvikt [17]3 years ago

3 0

Answer: -45j -9k

Step-by-step explanation:

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Yes u can because u always need to show er woek

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3 years ago

Find the common ratio of the geometric sequence: 12.5,−62.5,312.5,−1562.5,…

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Step-by-step explanation:

its what you multiply by to get the next number

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4 years ago

There are n questions on a multiple choice exam, and for each question, there are four choices. To pass the exam, one must corre

irinina [24]

Answer:

a) 0.352% probability of the student passing

b) 5

c) 1.875

Step-by-step explanation:

For each question, there are only two possible outcomes. Either the student answers it correctly, or he answers it wrong. The probability of correctly answering a question is independent from the probability of correctly answering 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.

The expected value of the binomial distribution is:

$E(X) = np$

The variance of the binomial distribution is:

$V(X) = np(1-p)$

For each question, there are four choices.

One choice is correct, so $p = \frac{1}{4} = 0.25$

a. Find the probability of the student passing for n = 10.

0.7*10 = 7

This is $P(X \geq 7)$ when $n = 10$

$P(X \geq 7) = P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)$

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

$P(X = 7) = C_{10,7}.(0.25)^{7}.(0.75)^{3} = 0.0031$

$P(X = 8) = C_{10,8}.(0.25)^{8}.(0.75)^{2} = 0.0004$

$P(X = 9) = C_{10,9}.(0.25)^{9}.(0.75)^{1} = 0.00002$

$P(X = 10) = C_{10,10}.(0.25)^{10}.(0.75)^{0} \cong 0$

$P(X \geq 7) = P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10) = 0.0031 + 0.0004 + 0.00002 = 0.00352$

0.352% probability of the student passing

b. Find the expected number of questions answered correctly for n = 20.

Here we have n = 20. So

$E(X) = np = 20*0.25 = 5$

c. Find the variance for the number of questions answered correctly for n = 10.

Here we have n = 10.

$V(X) = np(1-p) = 10*0.25*0.75 = 1.875$

5 0

4 years ago

Taymoor is going to apply for two different jobs. He estimates that

Ostrovityanka [42]

Answer:

0.58

Step-by-step explanation:

The probability that Taymoor gets at least one job is a sum of probabilities of 3 events:

1.He gets Job 1 (P(1.yes)= 0.3) and doesn't get the job 2 (P(2.not)=1-0.4=0.6)

P(1.yes,2.not)=P(1.yes)*P(2.not)=0.3*0.6=0.18

2. He doesn't get job1 (P(1.not)= 1-03=0.7 ) and gets job2(P2.yes)=0.4)

P(1.not,2.yes)=P(1.not)*P(2.yes)=0.7*0.4=0.28

3. He gets job1 (P(1.yes)= 0.3 ) and gets job2(P2.yes)=0.4)

P(1.yes,2.yes)=P(1.yes)*P(2.yes)=0.3*0.4=0.12

The resulted probability is P(gets job)= 0.18+0.28+0.12=0.58

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4 years ago

Rain falls steadily all day, dropping 2 inches of rain each hour. what does the graph look like

Irina-Kira [14]

think of it like this, after 1 hour there is 2 inches of rain, after 2 hours there is 4 inches of rain, and after 10, there should be 20, so, as it runs 1 it should rise 2.

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3 years ago

Read 2 more answers