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Basile [38]
2 years ago
11

Suppose the lifetime of a cell phone battery is normally distributed with a mean of 36 months and a standard deviation of 2 mont

hs. If the company wants to replace no more than 2% of all batteries, for how many months should they guarantee the lifetime of their batteries
Mathematics
1 answer:
solong [7]2 years ago
3 0

Answer:

They should guarantee the lifetime of their batteries for 32 months.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Mean of 36 months and a standard deviation of 2 months.

This means that \mu = 36, \sigma = 2

If the company wants to replace no more than 2% of all batteries, for how many months should they guarantee the lifetime of their batteries?

The guarantee should be the 2th percentile of lengths, which is X when Z has a pvalue of 0.02. So X when Z = -2.054.

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

-2.054 = \frac{X - 36}{2}

X - 36 = -2.054*2

X = 31.89

Rounding to the closest month, 32.

They should guarantee the lifetime of their batteries for 32 months.

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58,511 divieded by 21 the qoutient is 2,786 r?
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Answer:

5

Step-by-step explanation:

The answer is 5 Have fun

3 0
3 years ago
I really need help with this! Thank you!!
photoshop1234 [79]
<h3>Answer:</h3>
  1. x = 13; NP = 2 18/23 ≈ 2.8; NL = 5 5/23 ≈ 5.2
  2. D. x = 17, y = 5
<h3>Step-by-step explanation:</h3>

1. In order for this problem to be workable, we need to assume PQ ║ ML. Then ΔPNQ ~ ΔLNM and ∠L = ∠P = 60°.

... ∠L = 60°

... (3x+21)° = 60°

... 3x = 39 . . . . . . . divide by °, subtract 21

... x = 13 . . . . . . . . .divide by 3

The side lengths of similar triangles are proportional, so we have ...

... (3.2 cm)/y = (6 cm)/(8-y)

Multiplying by the product of the denominators, and dividing by (cm), we have ...

... 3.2(8 -y) = 6y

... 3.2×8 = 9.2y . . . . . add 3.2y

... y = 3.2×8/9.2 = 64/23 = 2 18/23 ≈ 2.78 = NP

Then ...

... 8-y = NL ≈ 5.22

In summary: x = 13; NP ≈ 2.8; NL ≈ 5.2

_____

2. If we assume figures ABCD and PSRQ are similar, we can find the values of the variables. We assume ∠C ≅ ∠R, so ...

... 4x +27° = 95°

... 4x = 68° . . . . . subtract 27°

... x = 17° . . . . . . . divide by 4

___

AB/AD = PS/PQ . . . . . corresponding sides of similar figures are proportional

... 4y/(3y-5) = 10/5 . . . . . units of ft cancel

... 5×4y = 10(3y -5) . . . . . multiply by 5(3y-5)

... 20y = 30y -50 . . . . . . simplify

... 50 = 10y . . . . . . . . . . . add 50-20y

... 5 = y . . . . . . . . . . . . . . divide by 10

Using this value of y, we have ...

AB = 4y ft = 20 ft; AD = (3y-5) ft = 10 ft. Both these values are double the corresponding lengths on PSRQ.

In summary, x = 17°, y = 5. . . . . . (note that the ° symbol is appropriate for x)

_____

You should have your teacher show you how to work these problems <em>using only the given information</em>.

In the second problem, you cannot start with the assumption that the figures are similar, as that is what you're being asked to prove. Please note, too, that two sides and one angle of a quadrilateral are insufficient to show similarity.

7 0
3 years ago
The operation denoted is by * is commutative and why?​
kipiarov [429]

Answer:

The commutative property of multiplication states that changing the order of the numbers we are multiplying, does not change the product.

3 0
2 years ago
Read 2 more answers
Omg pls help me i only have a few min left imma cry
hodyreva [135]

Answer:

option B

Step-by-step explanation:

since DA and CB are equal and originate from same line segmnet, they are parallel, so angle D and angle C are equal, angle A and anfle B are equal and angle E is the same for both,

4 0
3 years ago
Brainliest for best answer
-BARSIC- [3]

Answer:

Slope = -5/8

Step-by-step explanation:

Take 2 points from the graph where the line is. Point 1: (1 , 6). Point 2: (9 , 1).

We are going to use the formula for finding the slope of a line now.

y2 - y1/x2 - x1 = 1 - 6/9 - 1 = -5/8

Slope = -5/8

7 0
2 years ago
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