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zysi [14]
3 years ago
8

Can someone help me with these questions and show work please and thank you

Mathematics
1 answer:
attashe74 [19]3 years ago
6 0

Answer:

11. 78

12. 4x² - 3x - 1

Step-by-step explanation:

11. Sum of n whole numbers = ½(n² + n)

Multiply

½*n² + ½*n

= n²/2 + n/2

To find the sum of the first 12 whole number, substitute 12 for n into the equation.

= 12²/2 + 12/2

= 144/2 + 12/2

= 72 + 6

= 78

12. Area of trapezoid = ½(a + b)*h

Where,

a = 5x - 4

b = 3x + 2

h = x + 1

Area = ½(5x - 4 + 3x + 2)*(x + 1)

Area = ½(8x - 2)*(x + 1)

Area = ½[8x(x + 1) -2(x + 1)]

= ½[8x² + 8x - 2x - 2]

Add like terms

= ½(8x² - 6x - 2)

= ½(8x²) - ½(6x) - ½(2)

= 4x² - 3x - 1

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An IQ test is designed so that the mean is 100 and the standard deviation is 1414 for the population of normal adults. Find the
Amanda [17]

Answer:

37

Step-by-step explanation:

The first thing is to calculate critical z factor

the alpha and the critical z score for a confidence level of 90% is calculated as follows:

two sided alpha = (100% - 90%) / 200 = 0.05

critical z factor for two sided alpha of .05 is calculated as follows:

critical z factor = z factor for (1 - .05) = z factor for (.95) which through the attached graph becomes:

critical z factor = 2.58

Now we have the following formula:

ME = z * (sd / sqrt (N) ^ (1/2))

where ME is the margin of error and is equal to 6, sd is the standard deviation which is 14 and the value of z is 2.58

N the sample size and we want to know it, replacing:

6 = 2.58 * (14 / (N) ^ (1/2))

solving for N we have:

N = (2.58 * 14/6) ^ 2

N = 36.24

Which means that the sample size was 37.

5 0
4 years ago
What's the 8th term of the sequence defined by the given rule: F(1)=3, F (n-1 )+10
castortr0y [4]
Yes ofcourse maybe why
4 0
3 years ago
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What measurement is equelvent to 3 meters
Lelu [443]

Answer:

The Chi and Zhang were units of length equivalent to approximately 25 centimeters (9.8 inches) and 3 meters (9.8 feet) respectively.

Step-by-step explanation: 300 centimeters if you need metric measurements.

4 0
3 years ago
If the discount is 36% and the sale price is $32 what was the original price
jok3333 [9.3K]

Answer:

89

Step-by-step explanation:

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89

8 0
3 years ago
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NEED HELP ASAP.....At the 2012 Summer Olympic Games in London, in the Men's Shot Put qualifying round, the distances ranged from
jeka57 [31]

Answer:

About 6 athletes.

Step-by-step explanation:

We are concerned only with the percent of athletes that are above one standard deviation.

Between one standard deviation and two standard deviations, there is 13.6% of the athletes.

From 2 to 3, there is 2.1%. Above 3, there is 0.2%.

The sum of those percentages is 15.9% of 40 = 0.159 · 40 = 6.36 or about 6 athletes.

Hope this helps.

6 0
3 years ago
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