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3 years ago

1. -2b+9-(-5b)

Mathematics

1 answer:

scZoUnD [109]3 years ago

4 0

Is it due today cuz if not i’ll do it tonight

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A study of long-distance phone calls made from General Electric Corporate Headquarters in Fairfield, Connecticut, revealed the l

Anna [14]

Answer:

a) 0.4452

b) 0.0548

c) 0.0501

d) 0.9145

e) 6.08 minutes or greater

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 4.7 minutes

Standard Deviation, σ = 0.50 minutes.

We are given that the distribution of length of the calls is a bell shaped distribution that is a normal distribution.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

a) P(calls last between 4.7 and 5.5 minutes)

$P(4.7 \leq x \leq 5.5) = P(\displaystyle\frac{4.7 - 4.7}{0.50} \leq z \leq \displaystyle\frac{5.5-4.7}{0.50}) = P(0 \leq z \leq 1.6)\\\\= P(z \leq 1.6) - P(z$

$P(4.7 \leq x \leq 5.5) = 44.52\%$

b) P(calls last more than 5.5 minutes)

$P(x > 5.5) = P(z > \displaystyle\frac{5.5-4.7}{0.50}) = P(z > 1.6)\\\\P( z > 1.6) = 1 - P(z \leq 1.6)$

Calculating the value from the standard normal table we have,

$1 - 0.9452 = 0.0548 = 5.48\%\\P( x > 5.5) = 5.48\%$

c) P( calls last between 5.5 and 6 minutes)

$P(4.7 \leq x \leq 5.5) = P(\displaystyle\frac{5.5 - 4.7}{0.50} \leq z \leq \displaystyle\frac{6-4.7}{0.50}) = P(1.6 \leq z \leq 2.6)\\\\= P(z \leq 2.6) - P(z$

$P(5.5 \leq x \leq 6) = 5.01\%$

d) P( calls last between 4 and 6 minutes)

$P(4 \leq x \leq 6) = P(\displaystyle\frac{4 - 4.7}{0.50} \leq z \leq \displaystyle\frac{6-4.7}{0.50}) = P(-1.4 \leq z \leq 2.6)\\\\= P(z \leq 2.6) - P(z$

$P(4 \leq x \leq 6) = 91.45\%$

e) We have to find the value of x such that the probability is 0.03.

P(X > x)

$P( X > x) = P( z > \displaystyle\frac{x - 4.7}{0.50})=0.03$

$= 1 -P( z \leq \displaystyle\frac{x - 4.7}{0.50})=0.03$

$=P( z \leq \displaystyle\frac{x - 4.7}{0.50})=0.997$

Calculation the value from standard normal z table, we have,

P(z < 2.75) = 0.997

$\displaystyle\frac{x - 4.7}{0.50} = 2.75\\x = 6.075 \approx 6.08$

Hence, the call lengths must be 6.08 minutes or greater for them to lie in the highest 3%.

8 0

3 years ago

What is the distance between the tick marks on the number line?

lora16 [44]

Answer:

1/5

Step-by-step explanation:

2 units divided into 5 marks each = 10 marks

2/10 = 1/5 unit each mark

4 0

2 years ago

Read 2 more answers

Help plz! What is 823*25/h + 568 I'm so confused. If someone could help me that would be great thx! <3

balu736 [363]

Simplifying method:
20575/h + 568

h = 78 so:

20575/78 + 568

$78 \frac{64}{78} + 568$

$646 \frac{64}{78} = 646 \frac{32}{39}$

That's it!

4 0

4 years ago

Help please! <br> find the area of the isoceles triangle

DiKsa [7]

Answer:

This is a long answer. I got 82.5

Step-by-step explanation:

Area of isoceles triangle is

$\frac{1}{2} (b)(h)$

where b is the base and h is height.

Let draw a altuide going through Point D that split side FE into 2 equal lines. Let call that point that is equidistant from FE, H.

Since it is a altitude,it forms a right angle. So angle H=90.

Angle H is equidistant from F and E so

FH=11

EH=11.

The height is still unknown.

We can use pythagorean theorem to find side h but we need to know the slanted side or side DF to use the theorem.

Using triangle DFH, we know that angle H is 90 and angle F is 34. So using triangle interior rule,Angle D equal 56.

We know side FH=11
We know Angle D equal 56
We are trying to find side DF
We know angle H equal 90

We can use law of sines to find side DF

$\frac{fh}{ \sin(d) } = \frac{df}{ \sin(h) }$

Plug in the numbers

$\frac{11}{ \sin(56) } = \frac{df}{ \sin(90) }$

sin of 90 =1 so

$\frac{11}{ \sin(56) } = df$

Side df is about 13.3 inches.

Since we know our slanted side is 13.3 we can set up our pythagorean theorem equation,

$(fh) {}^{2} + (dh) {}^{2} = df {}^{2}$

$(11) {}^{2} +( dh) {}^{2} = (13.3) {}^{2}$

$121 + dh {}^{2} = 176.89$

$(dh) {}^{2} = 55.89$

$\sqrt{55.89} = 7.5$

is approximately 7.5 so dh=7.5 approximately.

Now using base times height times 1/2 multiply them out

$\frac{1}{2} (22)(7.5)$

$82.5$

8 0

3 years ago

Terrence plants a garden that has 8 rows of flowers, with 28 flower each row. How many flowers did Terrence plant?

My name is Ann [436]

28 * 8 = 224

Terrence planted 224 plants.

5 0

3 years ago

Read 2 more answers