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V125BC [204]
3 years ago
9

Can you plz help me I don’t understand at all

Mathematics
1 answer:
slamgirl [31]3 years ago
8 0

David made 30 cups of tea per hour. David worked for D hours. In D hours, he made 30D cups of tea. Then he made an additional 10 cups of tea, so this week, he made 30D + 10 cups of tea.

Andrew made 35 cups of coffee per hour. Andrew worked for A hours. In A hours, he made 35A cups of tea.

The total cups of tea and coffee made this week is:

30D + 10 + 35A

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Find f(2) if f(x)=2x+1
IgorLugansk [536]
Answer: 5

Work Shown:
f(x) = 2x+1
f(2) = 2*2+1 ... x has been replaced with 2
f(2) = 4+1
f(2) = 5
The input is x = 2. The output is y = 5. 
3 0
3 years ago
The exterior angles of an octagon are 42°, 55°, 39°, 20°, 62°, 45°, and 47°. What is the measure of the eighth exterior angle? S
marysya [2.9K]
The sum of exterior angles of a polygon = 360<span>°

Thus, the eighth exterior angle is equal to
360</span>° - (42° + 55° + 39° + 20° + 62° + 45° + 47°) = 50<span>°</span> 
6 0
3 years ago
Read 2 more answers
The dwarves of the Grey Mountains wish to conduct a survey of their pick-axes in order to construct a 99% confidence interval ab
Dmitry_Shevchenko [17]

Answer:

The minimum sample size needed is 125.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of \pi, and a confidence level of 1-\alpha, we have the following confidence interval of proportions.

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which

z is the zscore that has a pvalue of 1 - \frac{\alpha}{2}.

The margin of error is:

M = z\sqrt{\frac{\pi(1-\pi)}{n}}

For this problem, we have that:

\pi = 0.25

99% confidence level

So \alpha = 0.01, z is the value of Z that has a pvalue of 1 - \frac{0.01}{2} = 0.995, so Z = 2.575.

What minimum sample size would be necessary in order ensure a margin of error of 10 percentage points (or less) if they use the prior estimate that 25 percent of the pick-axes are in need of repair?

This minimum sample size is n.

n is found when M = 0.1

So

M = z\sqrt{\frac{\pi(1-\pi)}{n}}

0.1 = 2.575\sqrt{\frac{0.25*0.75}{n}}

0.1\sqrt{n} = 2.575{0.25*0.75}

\sqrt{n} = \frac{2.575{0.25*0.75}}{0.1}

(\sqrt{n})^{2} = (\frac{2.575{0.25*0.75}}{0.1})^{2}

n = 124.32

Rounding up

The minimum sample size needed is 125.

5 0
4 years ago
two blocks of wood are shaped as right rectangular prism the smaller block has a length of 9 cm and a width of 3 cm and a height
AlexFokin [52]

Answer:

1512 cm³

Step-by-step explanation:

Formula

Volume of right rectangular prism = Length × Breadth × Height

As given

Two blocks of wood are shaped as right rectangular prisms.

The smaller block has a length of 9 cm, a width of 3 cm, and a height of 7 cm.

As given

The dimensions of the larger block are double the dimensions of the smaller block.

Length of the larger block = 2 × Length of the smaller block

                                           = 2 × 9

                                           = 18 cm

Breadth of the larger block = 2 × Breadth of the smaller block

                                           = 2 × 3

                                           = 6 cm

Height of the larger block = 2 × Height of the smaller block

                                           = 2 × 7

                                           = 14 cm

Put in the formula

Volume of larger wooden block = 18 × 6 × 14

                                                    = 1512 cm³

Therefore the volume of the wooden block is 1512 cm³ .

7 0
3 years ago
Read 2 more answers
4x^2-7x=15<br> Solve by factoring and please please please explain or show the work
vodomira [7]

Answer:

x=3 and x=-1.25

Step-by-step explanation:

4x^2-7x=15

subtract 15 from each side:

4x^2-7x-15=0

factor  (trying different numbers that the sum is 7 and the quotient is 15)

(2x-6 )(2x+2.5 )=0

2x-6=0 add 6 to each side

2x=6

x=3

2x+2.5=0   subtract 2.5 from each side

2x=-2.5

x=-1.25

8 0
3 years ago
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