Select all the expressions that are equivalent to –25(15

1.1 puzzle time did you hear about the trees birthday

Zigmanuir [339]

Answer:

It was a sappy one

Step-by-step explanation:

lol

6 0

1 year ago

Nakita rode her skateboard at an average speed of 8.8 feet per second for 0.2 miles. She wants to calculate how long it took her

timama [110]

Answer: $2\ minutes$

Step-by-step explanation:

We know that:

$d=rt$

Where "d" is distance, "r" is rate and "t" is time.

Solved for the time "t":

$t=\frac{d}{r}$

The first step is to convert the distance from miles to feet.

Since $1\ mile=5,280\ feet$ , we get:

$d=(0.2\ mi)(\frac{5,280\ ft}{1\ mi})\\\\d=1,056\ ft$

Knowing that:

$r=8.8\ \frac{ft}{s}$

We can substitute values into $t=\frac{d}{r}$ in order to find the time in seconds:

$t=\frac{1,056\ ft}{8.8\ \frac{ft}{s}}\\\\t=120\ s$

Since:

$1\ minute = 60\ seconds$

The time in minutes is:

$t=(120\ s)(\frac{1\ min}{60\ s})\\\\t=2\ min$

7 0

2 years ago

An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed, with mean equ

kompoz [17]

Answer:

0.62% probability that a random sample of 16 bulbs will have an average life of less than 775 hours.

Step-by-step explanation:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , a large sample size can be approximated to a normal distribution with mean $\mu$ and standard deviation $\frac{\sigma}{\sqrt{n}}$

Normal probability distribution.

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 800, \sigma = 40, n = 16, s = \frac{40}{\sqrt{16}} = 10$

Find the probability that a random sample of 16 bulbs will have an average life of less than 775 hours.

This probability is the pvalue of Z when $X = 775$ . So

$Z = \frac{X - \mu}{s}$

$Z = \frac{775 - 800}{10}$

$Z = -2.5$

$Z = -2.5$ has a pvalue of 0.0062. So there is a 0.62% probability that a random sample of 16 bulbs will have an average life of less than 775 hours.

5 0

2 years ago

Which is a factor of the polynomial f(x) = 6x4 – 21x3 – 4x2 + 24x – 35?

QveST [7]

<span>I note that this problem starts out with "Which is a factor of ... " This implies that you were given several answer choices. If that's the case, it's unfortunate that you haven't shared them.

I thought I'd try finding roots of this function using synthetic division. See below:

f(x) = 6x^4 – 21x^3 – 4x^2 + 24x – 35
Please use " ^ " to denote exponentiation. Thanks.

Possible zeros of this poly are factors of 35: plus or minus 1, plus or minus 5, plus or minus 7. Use synthetic division; determine whether or not there is a non-zero remainder in each case. If none of these work, form rational divisors from 35 and 6 and try them: 5/6, 7/6, 1/6, etc.

Provided that you have copied down the function
</span>f(x) = 6x^4 – 21x^3 – 4x^2 + 24x – 35 properly, this approach will eventually turn up 1 or 2 zeros of this poly. Obviously it'd be much easier if you'd check out the possible answers given you with this problem.

By graphing this function, I found that the graph crosses the x-axis at 7/2. There is another root.

Using synth. div. to check whether or not 7/2 is a root:

___________________________
7/2 / 6 -21 -4 24 -35
21 0 -14 35
----------- ------------------------------
6 0 -4 10 0

Because the remainder is zero, 7/2 (or 3.5) is a root of the polynomial. Thus, (x-3.5), or (x-7/2), is a factor.

7 0

1 year ago

Read 2 more answers

A company plans to ship 2,000 packages of chocolate. The company randomly selects 100 packages and finds that five packages have

Anna71 [15]

100 packages should have an incorrect weight

3 0

1 year ago

Select all the expressions that are equivalent to –25(15 – 20d + 5c).