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4 years ago

Please help iready math

Mathematics

2 answers:

Kamila [148]4 years ago

8 0

Answer:

-4+(-9)

Step-by-step explanation:

You change the minus signs into and addition sign and make the number a negative.

Marat540 [252]4 years ago

4 0

Answer:

-4+(-9)

Step-by-step explanation:

because -4-9= -13 and -4+(-9)=-13

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Tate is trying to decide if he should spend $100 to purchase virus protection software for his new computer

Darina [25.2K]

Answer: Hello your question is vague hence I will give a more general answer

answer : Tate spending $100 to purchase virus protection will help protect his computer from Viruses that can cause Damages worth more than $100. therefore he should purchase the virus protection.

Step-by-step explanation:

Virus protection software ( i.e. Anti-virus software) is a set of computer programs written into the computer or any other electronic Gadget like a Phone with the purpose of protecting, detecting and removing malicious software ( computer viruses ) from the computer

7 0

3 years ago

an open box is to be made from a piece of metal 16 by 30 inches by cutting out squares of equal size from the corners and bendin

blagie [28]

Let the lengths of the bottom of the box be x and y, and let the length of the squares being cu be z, then
V = xyz . . . (1)
2z + x = 16 => x = 16 - 2z . . . (2)
2z + y = 30 => y = 30 - 2z . . . (3)

Putting (2) and (3) into (1) gives:
V = (16 - 2z)(30 - 2z)z = z(480 - 32z - 60z + 4z^2) = z(480 - 92z + 4z^2) = 480z - 92z^2 + 4z^3
For maximum volume, dV/dz = 0
dV/dz = 480 - 184z + 12z^2 = 0
3z^2 - 46z + 120 = 0
z = 3 1/3 inches

Therefore, for maximum volume, a square of length 3 1/3 (3.33) inches should be cut out from each corner of the cardboard.
The maximum volume is 725 25/27 (725.9) cubic inches.

8 0

3 years ago

The patient recovery time from a particular surgical procedure is normally distributed with a mean of 4 days and a standard devi

Gelneren [198K]

Answer:

a) N(4, 1.6)

b) 4 days

c) $Z = 0.69$

d) There is a 30.85% probability of spending more than 4.8 days in recovery.

e) There is a 11.62% probability of spending between 3.2 and 3.7 days in recovery.

f) The 90th percentile for recovery times is 6.05 days.

Step-by-step explanation:

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:

Mean of 4 days and a standard deviation of 1.6 days. So $\mu = 4, \sigma = 1.6$ .

a. What is the distribution of X?

This is normal with mean 4 and standard deviation 1.6. So N(4, 1.6).

b. What is the median recovery time?

For the normal distribution, the median is the same as the mean. So the median recovery time is 4 days.

c. What is the Z-score for a patient that took 5.1 days to recover?

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

$Z = \frac{5.1 - 4}{1.6}$

$Z = 0.69$

d. What is the probability of spending more than 4.8 days in recovery?

This probability is 1 subtracted by the pvalue of Z when $X = 4.8$ . So

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

$Z = \frac{5.8 - 4}{1.6}$

$Z = 0.5$

$Z = 0.5$ has a pvalue of 0.6915.

This means that there is a 1-0.6915 = 0.3085 = 30.85% probability of spending more than 4.8 days in recovery.

e. What is the probability of spending between 3.2 and 3.7 days in recovery?

This probability is the pvalue of Z when X = 3.7 subtracted by the pvalue of Z when X = 3.2. So:

X = 3.7

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

$Z = \frac{3.7 - 4}{1.6}$

$Z = -0.19$

$Z = -0.19$ has a pvalue of 0.4247

X = 3.2

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

$Z = \frac{3.2 - 4}{1.6}$

$Z = -0.5$

$Z = -0.5$ has a pvalue of 0.3085

This means that there is a 0.4247 - 0.3085 = 0.1162 = 11.62% probability of spending between 3.2 and 3.7 days in recovery.

f. The 90th percentile for recovery times is

This probability is the value of X when Z has a pvalue of 0.90. So it is X when Z = 1.28.

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

$1.28 = \frac{X - 4}{1.6}$

$X = 4 = 1.28*1.6$

$X = 6.05$

The 90th percentile for recovery times is 6.05 days.

7 0

3 years ago

QUICK 64 Divded by 8

ch4aika [34]

Answer:

8! 8x8=64 lol

Step-by-step explanation:

Hope this helps, And have a good day!

6 0

3 years ago

Will give brainliest!!!!<br>Explain how solving -7y > 161 is different from solving 7y > -161.

Jlenok [28]

To solve -7y > 161, we divide both sides by -7 and we get y < -23. The inequality sign flipped because we divided both sides by a negative number.

To solve 7y > -161, we divide both sides by 7 and it leads to y > -23. The inequality sign does not flip in this case, because we are not dividing both sides by a negative number.

The similarities is that we end up with -23 on the right side, but the inequality signs are different.

5 0

3 years ago