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WARRIOR [948]
3 years ago
10

tess has 100 dimes and quarters , if the total of the coins is $21.40 how many of each of the coins does she have ?? Using subst

itution or elimination find the answer
Mathematics
1 answer:
Zanzabum3 years ago
4 0

Answer: 24 and 76

Step-by-step explanation:

{

d

+

q

=

100

10

d

+

25

q

=

2140

From the first equation, we have  

d

=

100

−

q

Substituting that into the second equation, we have

10

(

100

−

q

)

+

25

q

=

2140

⇒

1000

−

10

q

+

25

q

=

2140

⇒

15

q

=

1140

⇒

q

=

1140

15

=

76

Knowing that  

q

=

76

we can substitute that value into the first equation to obtain

d

+

76

=

100

∴

d

=

24

Thus, Sue has  

24

dimes and  

76

quarters.

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a source of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b an
marissa [1.9K]
Let  AM be the distance between point A and the right wall and AN be the distance between A and the left wall.
Δ AMB is an isosceles right triangle and  Δ ANC is half of an equilateral triangle.
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3 years ago
Jett has to sell carnival tickets worth at least $50. The price of a child ticket is $4, and the price of an adult ticket is $6.
Tpy6a [65]

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Step-by-step explanation:

The answer is A. 4x + 6y is greater than or equal to 50

7 0
3 years ago
Q # 7 please help to solve
Neko [114]
The fourth choice - 5/104.

In one cube, there are 3 even numbers - 2,4,6. For two cubes, the total probability is 36.
   3*3 / 36 = 9/36

For letters, there are five vowels over 26 letters = 5 / 26

Multiply the two probabilities to get the probability of rolling two even numbers and selecting one of the vowels.
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6 0
3 years ago
Health insurers are beginning to offer telemedicine services online that replace the common office visit. A company provides a v
Veronika [31]

Answer:

\text {CI} = (60.54, \: 81.46)\\\\

Therefore, we are 95% confident that actual mean savings for a televisit to the doctor is within the interval of ($60.54 to $81.46)

Step-by-step explanation:

Let us find out the mean savings for a televisit to the doctor from the given data.

Using Excel,

=AVERAGE(number1, number2,....)

The mean is found to be

\bar{x} = \$71  

Let us find out the standard deviation of savings for a televisit to the doctor from the given data.

Using Excel,

=STDEV(number1, number2,....)

The standard deviation is found to be

 s = \$ 22.35

The confidence interval is given by

\text {confidence interval} = \bar{x} \pm MoE\\\\

Where the margin of error is given by

$ MoE = t_{\alpha/2}(\frac{s}{\sqrt{n} } ) $ \\\\

Where n is the sample of 20 online doctor visits, s is the sample standard deviation and t_{\alpha/2} is the t-score corresponding to a 95% confidence level.

The t-score is given by is

Significance level = α = 1 - 0.95 = 0.05/2 = 0.025

Degree of freedom = n - 1 = 20 - 1 = 19

From the t-table at α = 0.025 and DoF = 19

t-score = 2.093

So, the margin of error is

MoE = t_{\alpha/2}(\frac{s}{\sqrt{n} } ) \\\\MoE = 2.093\cdot \frac{22.35}{\sqrt{20} } \\\\MoE = 2.093\cdot 4.997\\\\MoE = 10.46\\\\

So the required 95% confidence interval is

\text {CI} = \bar{x} \pm MoE\\\\\text {CI} = 71 \pm 10.46\\\\\text {CI} = 71 - 10.46, \: 71 + 10.46\\\\\text {CI} = (60.54, \: 81.46)\\\\

Therefore, we are 95% confident that actual mean savings for a televisit to the doctor is within the interval of ($60.54 to $81.46)

7 0
3 years ago
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