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34kurt
3 years ago
5

The ages of commercial aircraft are normally distributed with a mean of 13.5 years and a standard deviation of 7.3 years. what p

ercentage of individual aircraft have ages greater than 15 ​years? assume that a random sample of 49 aircraft is selected and the mean age of the sample is computed. what percentage of sample means have ages greater than 15 ​years?
Mathematics
1 answer:
Artist 52 [7]3 years ago
7 0
Answer: The percent higher is 41.68%. If 49 planes were selected, 20 of them should be above 15 years.

To find the percent, we first need the z-score.

(15 - 13.5) / 7.3 = 0.21

Now, use a normal distribution table to find the percent above a score of 0.21. It will be 41.68%.

To find the number of 49 planes above this value, multiply 49 by 0.4168. You will have about 20.4 planes.
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Geometry question I need help with it
Snowcat [4.5K]

Answer:

True, False, False, False

Step-by-step explanation:

I'll find the lengths of all sides of the drawing before answering individual answers so that it's less confusing.

1) The question says that QR is a perpendicular bisector of TS. This means that the length of TQ and QS is the same. Also, since both triangles TRQ and SRQ share the same side RQ, and the angle between the two segments is 90 degrees, the two triangles are congruent (RTQ and RSQ) using SAS.

2) Side RT and TS will have the same length since the two triangles are congruent. (2x+1) = (4x-3) --> -2x = -4 --> x = 2. We can conclude that x = 2.

3) Now that we know that x = 2, we can find the length of side RS by replacing the x with 2. 4(2)-3 is 5, so RS = 5.

4) We can use the Pythagorean theorem to find RQ (Hypotenuse^2 = Other two sides added after being squared individually). Since the hypotenuse of triangle RSQ is RS which is 5, and one side is 4, we can input those into our equation. (5)^2 = (4)^2 + (RQ)^2. --> 25 = 16 + (RQ)^2 --> 9 = (RQ)^2 --> RQ = 3.

5) Since the two triangles RTQ and RSQ are congruent, side TQ and SQ also have the same length, since CPCTC (Corresponding parts of congruent triangles are congruent). QS is 4, so TQ will also be 4. This means that ST will be 8 (4+4). ST = 8

Now that we have all the clues, all we need to do is choose True or False.

RS = 5 is TRUE

RS = 4 is FALSE

ST = 10 is FALSE

QR = 4 is FALSE

6 0
2 years ago
Evan was carrying forward a balance of $300 from the previous month. His annual interest rate is 30%. Use computation to determi
sattari [20]

<u>Answer</u>:

The interest charged for this month is $7.5

<u>Step-by-step explanation:</u>

Given:

Principal = $300

Interest = 30%

Time =  1 month

To Find:  

The interest charged for this month = ?

Solution:

we know that the  interest charged = principal \times \text {Interest rate} \times time

1 month can also be written as \frac{1}{12}

Substituting the values,

interest charged:

=> 300 \times 30%  \times \frac{1}{12}

=> 300 \times \frac{30}{100} \times \frac{1}{12}

=> 300 \times \frac{3}{120}

=>\frac{900}{120}

=>\frac{30}{4}

=>\frac{15}{2}

=> 7.5

6 0
3 years ago
Find the range of the graphed function.
rusak2 [61]

Range is set of all y-values. To find a range of graphed function, we need to know that range starts from the minimum value of graph to maximum value. That's because the minimum value is the least value that you can get by substituting the domain and the maximum value is the largest value that you can get by substituting the domain as well.

Now we don't talk about domain here, we talk about range. See the attachment! You are supposed to focus on y-axis, plane or vertical line. See how the minimum value of function is the negative value while the maximum value is positive.

That means any ranges that don't contain the negative values are cleared out. (Hence A and C choices are wrong.)

Next, range being set of all real numbers mean that graphed functions don't have maximum value or minimum value (We can say that both max and min are infinite.)

Take a look at line graph as an example of range being set of all real numbers, or cubic function.

Answer/Conclusion

  • The range exists from negative value which is -9 to the maximum value which is 5.
  • That means the range is -9<=y<=5

3 0
3 years ago
Can some one help me asap
zavuch27 [327]
It'd be easier to do #18 if y ou were to break it up:

                                                        14* (first term + 14th term)
Sum from n=1 to 14 of n =  S      = ---------------------------------
                                               14                       2
                                    
     14(1+14)
= ---------------- = 7(15) = 105 
           2

The sum of twice that is 210.  The sum of "1 from n=1 to n=14" is just 14.

The final sum is 210 + 14 = 224 (answer)
4 0
3 years ago
Find the missing dimension of the triangle.<br> Area = 14 ft2<br> height= 6 ft<br> base=???
Bas_tet [7]

Answer:

b=4.67ft

Step-by-step explanation:                                                                                    The steps are in the picture below.

4 0
3 years ago
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