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belka [17]
3 years ago
7

Assuming a normal distribution, families spends an average of $500 on their monthly cell phone bills with a standard deviation o

f $75. what is the probability a random families' bill is between $350 and $400?
Mathematics
1 answer:
lara [203]3 years ago
8 0
The probability is 0.69.

We find the z-scores that correspond with each end of the range we're looking for.  To find a z-score, we use the formula:
z=\frac{X-\mu}{\sigma}
\\
\\=\frac{350-500}{75}=\frac{-150}{75}=-2

z=\frac{400-500}{75}=\frac{-100}{75}=-1.33

Using a z-table (http://www.z-table.com) we see that the area under the curve left of the score 350 would be 0.228.  The area under the curve left of the score 400 would be 0.918.  To find just the range between 350 and 400, we subtract the area left of 350 from the area left of 400; this will give us just from 350 to 400:

0.918-0.228 = 0.69.
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Saj has made 7 litres of curry sauce.
Makovka662 [10]

Answer:

18 jars can be filled completely.

Step-by-step explanation:

7L=7000ml

1 jar contain 375 ml

375ml can be filled in 1 jar

375ml=1 jar

1 ml = 1/375 jar

7000 ml = 7000× 1/375 jar

7000ml= 18.67 jar

hence 18 jars can be filled completely.

3 0
2 years ago
When the sum of 5 and three times a positive number is subtracted from the square of the number, 0 results. Find the number.
Juliette [100K]
x-the\ number\\\\x^2-(5+3x)=0\\\\x^2-5-3x=0\\\\x^2-3x-5=0

Use\ the\ quadratic\ formula:\\a^2x+bx+c=0\\\\\Delta=b^2-4ac\\\\if\ \Delta > 0\ then\ x_1=\dfrac{-b-\sqrt\Delta}{2a}\ and\ x_2=\dfrac{-b+\sqrt\Delta}{2a}\\\\if\ \Delta=0\ then\ x_0=\dfrac{-b}{2a}\\\\if\ \Delta < 0\ then\ no\ solution

x^2-3x-5=0\\\\a=1;\ b=-3;\ c=-5\\\\\Delta=(-3)^2-4\cdot1\cdot(-5)+3+20=29 \ \textgreater \  0\\\\\sqrt\Delta=\sqrt{29}\\\\x_1=\dfrac{3-\sqrt{29}}{2\cdot1}=\dfrac{3-\sqrt{29}}{2} \ \textless \  0\\\\x_2=\dfrac{3+\sqrt{29}}{2\cdot1}=\dfrac{3+\sqrt{29}}{2} \ \textgreater \  0

Answer:\ \boxed{x=\dfrac{3+\sqrt{29}}{2}}
6 0
2 years ago
Which of the following is a rational number?
ioda
The rational number would be 16
8 0
2 years ago
What is the maximum height of of Anna's golf ball? The equation is y=x−0.04x2.
elena-s [515]

Given:

The height of a golf ball is represented by the equation:

y=x-0.04x^2

To find:

The maximum height of of Anna's golf ball.

Solution:

We have,

y=x-0.04x^2

Differentiate with respect to x.

y'=1-0.04(2x)

y'=1-0.08x

For critical values, y'=0.

1-0.08x=0

-0.08x=-1

x=\dfrac{-1}{-0.08}

x=12.5

Differentiate y' with respect to x.

y''=(0)-0.08(1)

y''=-0.08

Since double derivative is negative, the function is maximum at  x=12.5.

Substitute x=12.5 in the given equation to get the maximum height.

y=(12.5)-0.04(12.5)^2

y=12.5-0.04(156.25)

y=12.5-6.25

y=6.25

Therefore, the maximum height of of Anna's golf ball is 6.25 units.

7 0
3 years ago
Please some answer this I need help!! What is A b g h j d c f e k?
Karolina [17]

Answer:there is no g .no h

Step-by-step explanation:how can we tell u have a calculator right

4 0
2 years ago
Read 2 more answers
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