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3 years ago

Find the sum using distributive property 72+9

Mathematics

1 answer:

andrew-mc [135]3 years ago

5 0

Answer:

72 + 9 = 9(8 + 1) = 9(9) = 81

Step-by-step explanation:

Starting with 72 + 9, factor out the 9, obtaining 9(8 + 1),

which in turn can be rewritten as 9(9). Multplying, we get 81. This is the final answer, equivalent to 72 + 9.

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Suppose the average tread-life of a certain brand of tire is 42,000 miles and that this mileage follows the exponential probabil

Ahat [919]

Answer: The probability that a randomly selected tire will have a tread-life of less than 65,000 miles is 0.7872 .

Step-by-step explanation:

The cumulative distribution function for exponential distribution is :-

$P(X\leq x)=1-e^{\frac{-x}{\lambda}}$ , where $\lambda$ is the mean of the distribution.

As per given , we have

Average tread-life of a certain brand of tire : $\lambda=\text{42,000 miles }$

Now , the probability that a randomly selected tire will have a tread-life of less than 65,000 miles will be :

$P(X\leq 65000)=1-e^{\frac{-65000}{42000}}\\\\=1-e^{-1.54761}\\\\=1-0.212755853158\\\\=0.787244146842\approx0.7872$

Hence , the probability that a randomly selected tire will have a tread-life of less than 65,000 miles is 0.7872 .

8 0

3 years ago

A public bus company official claims that the mean waiting time for bus number 14 during peak hours is less than 10 minutes. Kar

ch4aika [34]

Answer:

We conclude that the mean waiting time is less than 10 minutes.

Step-by-step explanation:

We are given that a public bus company official claims that the mean waiting time for bus number 14 during peak hours is less than 10 minutes.

Karen took bus number 14 during peak hours on 18 different occasions. Her mean waiting time was 7.8 minutes with a standard deviation of 2.5 minutes.

Let $\mu$ = mean waiting time for bus number 14.

So, Null Hypothesis, $H_0$ : $\mu \geq$ 10 minutes {means that the mean waiting time is more than or equal to 10 minutes}

Alternate Hypothesis, $H_A$ : $\mu$ < 10 minutes {means that the mean waiting time is less than 10 minutes}

The test statistics that would be used here One-sample t test statistics as we don't know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean waiting time = 7.8 minutes

s = sample standard deviation = 2.5 minutes

n = sample of different occasions = 18

So, test statistics = $\frac{7.8-10}{\frac{2.5}{\sqrt{18} } }$ ~ $t_1_7$

= -3.734

The value of t test statistics is -3.734.

Now, at 0.01 significance level the t table gives critical value of -2.567 for left-tailed test.

Since our test statistic is less than the critical value of t as -3.734 < -2.567, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the mean waiting time is less than 10 minutes.

5 0

3 years ago

PLEASE HELP!! ASAP !!! WILL MARK BRAINLEST! Answer choices ○ 0° ○180° ○270°

AlladinOne [14]

Answer:

270° counterclockwise

Step-by-step explanation:

8 0

2 years ago

Read 2 more answers

Please help me i need it bad.

AnnyKZ [126]

Answer:

B. Q' (1, 2)

Step-by-step explanation:

im good like that :)

also you can just count how far the Q is from P and R idk how to explain

4 0

2 years ago

A political polling agency predicts candidate A will win an election with 63% of the votes. Their poll has a margin of error of

scoray [572]

Answer:

56% ≤ p ≤ 70%

Step-by-step explanation:

Given the following :

Predicted % of votes to win for candidate A= 63%

Margin of Error in prediction = ±7%

Which inequality represents the predicted possible percent of votes, x, for candidate A?

Let the interval = p

Hence,

|p - prediction| = margin of error

|p - 63%| = ±7%

Hence,

Upper boundary : p = +7% + 63% = 70%

Lower boundary : p = - 7% + 63% = 56%

Hence,

Lower boundary ≤ p ≤ upper boundary

56% ≤ p ≤ 70%

5 0

3 years ago