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2 years ago

How many permutations of a 7-digit phone number exist if any number 0-9 may be used but repetition is not allowed?

Mathematics

1 answer:

Blizzard [7]2 years ago

5 0

Answer:

10!/3!

Step-by-step explanation:

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A researcher wants to see if a kelp extract helps prevent frost damage on tomato plants. One hundred tomato plants in individual

Anna11 [10]

Answer:

The 95% confidence interval for the true difference in the proportion of tomato plants like these that would experience damage after receiving the kelp treatment and no kelp treatment is -0.2690 < $\hat{p}_1-\hat{p}_2$ < 0.02901

Step-by-step explanation:

The given data are;

The number of the group 1 plants that exhibited damage = 12

The number of plants in group 1, n₁ = 50

The number of the group 2 plants that exhibited damage = 18

The number of plants in group 2, n₂ = 50

The proportion of group 1 plants that exhibited damage, $\hat p_1$ = 12/50 = 0.24

The proportion of group 2 plants that exhibited damage, $\hat p_2$ = 18/50 = 0.36

The z-value at 95% = 1.64

The confidence interval is given by the following formula;

$C.I. = \hat{p}_1-\hat{p}_2\pm z^{*}\sqrt{\dfrac{\hat{p}_1\left (1-\hat{p}_1 \right )}{n_{1}}+\dfrac{\hat{p}_2\left (1-\hat{p}_2 \right )}{n_{2}}}$

Plugging in the values, we get;

$C.I. = 0.24-0.36\pm 1.64 \times \sqrt{\dfrac{0.24\left (1-0.24 \right )}{50}+\dfrac{0.36\left (1-0.36 \right )}{50}}$

Therefore, C.I. = -0.2690 < $\hat{p}_1-\hat{p}_2$ < 0.02901

7 0

3 years ago

What is the value of n in the equation –(2n + 4) + 6 = –9 + 4(2n + 1)?

agasfer [191]

–(2n + 4) + 6 = –9 + 4(2n + 1)

-2n - 4 + 6 = - 9 + 4*2n + 4*1

-2n - 4 + 6 = - 9 + 8n + 4

Take all the n's to one side and numbers to the other side. Sign changes to + or - when equality sign is crossed to other side of equation.

-2n - 8n = - 9 + 4 + 4 -6

-10n = -7

n = -7/-10

n = 7/10 or 0.7

8 0

3 years ago

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Suzannah made 7 bows. How many feet of ribbon did she use?

ella [17]

Answer:

420

Step-by-step explanation:

5 0

3 years ago

If you have 16 cups of sugar , 2 cups of sugar for every batch of cookies , but you have to save 6 cups of sugar for something e

sesenic [268]

The first step we want to take here is to subtract 6 cups of sugar since we'll need it for something else, leaving us with 10 cups of sugar. It takes 2 cups of sugar for every batch of cookies, so you're going to divide 10 by 2. Luckily, 2 is a multiple of 10 so it's a whole number. By dividing, we get 5. So, we can make 5 batches of cookies while still saving 6 cups of sugar for something else.

8 0

3 years ago

For the inverse variation equation p=8/V, what is the value of V when p=4?

mafiozo [28]

4 = 8 / V
4V = 8
V = 8/4
V = 2

6 0

3 years ago

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