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3 years ago

What is the next number in the sequence? 55, 34, 21, 13, 8…?

Mathematics

1 answer:

Svetllana [295]3 years ago

4 0

The next number is 5.

Each number in the sequence is the (positive) difference of the previous two numbers.

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Consider a paint-drying situation in which drying time for a test specimen is normally distributed with σ = 7. The hypotheses H0

pshichka [43]

Answer:

(a) The value $\bar x$ = 72.3 is 1.21 standard deviations below the null value of μ.

(b) The mean drying time of paint is not less than 74.

Step-by-step explanation:

The hypothesis for the single mean test is:

H₀: μ = 74 vs. Hₐ: μ < 74.

The information provided is:

σ = 7

n = 25

As the population standard deviation is known, we will use a z-test for single mean.

(a)

The z-score is a Normal distribution with mean 0 and variance 1. It is also defined as the number of standard deviations a raw score is from the mean.

The z-score for sample mean is given by:

$z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}$

If $\bar x$ = 72.3 compute the corresponding z-score as follows:

$z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}$

$=\frac{72.3-74}{7/\sqrt{25}}\\=-1.21$

Thus, the value $\bar x$ = 72.3 is 1.21 standard deviations below the null value of μ.

(b)

So the test statistic is, z = -1.21.

Compute the p-value of the test as follows:

$p-value=P(Z$

*Use a z-table.

The decision rule says to, reject the null hypothesis if the p-value is less than the significance level α = 0.01 and vice-versa.

p-value = 0.1131 < α = 0.01

The null hypothesis was failed to be rejected.

Thus, the mean drying time of paint is not less than 74.

6 0

2 years ago

Which is the better buy on potatoes? 3 lbs. for $.90 5 lbs. for $1.60

myrzilka [38]

Answer:

3 pounds for 90 cents.

Step-by-step explanation:

The 5 pound bag costs 32 cents a pound

The 3 pound bag is 30 cents a pound

7 0

2 years ago

Q2.What is the ratio of volumes of the two cylinders formed by rolling a sheet of dimensions lxb in two different ways? Q3.What

Kobotan [32]

Answer:

2. b : l

3. 20cm

4. 49 $cm^{2}$

5. $(2\pi+1):2\pi$

Step-by-step explanation:

Solution 2:

Let cylinder is rolled along 'l':

Height of cylinder , h = length of rectangle = l

Perimeter of base = b

Let 'r' be the radius of cylinder's base:

$2\pi r = b\\\Rightarrow r = \dfrac{b}{2\pi}$

Volume of a cylinder is given as:

$V = \pi r^{2} h$

Putting the values:

$V_1 = \pi (\dfrac{b}{2\pi})^2 l\\\Rightarrow V_1 = (\dfrac{b^2}{4\pi}) l$

Let cylinder is rolled along 'b':

Height of cylinder , h = length of rectangle = b

Perimeter of base = l

Let 'r' be the radius of cylinder's base:

$2\pi r = l\\\Rightarrow r = \dfrac{l}{2\pi}$

Volume of a cylinder is given as:

$V = \pi r^{2} h$

Putting the values:

$V_2 = \pi (\dfrac{l}{2\pi})^2 b\\\Rightarrow V_2 = (\dfrac{l^2}{4\pi}) b$

Taking ratio:

$V_1:V_2 = \dfrac{(\dfrac{b^2}{4\pi}) l}{(\dfrac{l^2}{4\pi}) b} = b:l$

Solution 3:

Rectangle is rolled along its length to make a cylinder, so height will be equal to its length.

$\therefore$ height of cylinder = 20 cm

Solution 4:

Side of square = 7 cm

Height of cylinder =Side of square = 7 cm

7 cm will be the circumference of the circle.

i.e. $2\pi r$ = 7 cm

Curved surface area of a cylinder:

$CSA = 2\pi rh$

Putting the above values:

CSA = 7 $\times$ 7 = 49 $cm^{2}$

Solution 5:

As calculated in above step:

CSA = $2\pi rh =$ 7 $\times$ 7 = 49 $cm^{2}$

Total surface area = $2\pi r^{2} + 2\pi r h$

Calculating value of r:

$2\pi r$ = 7 cm

$\Rightarrow 2 \pi r = 7\\\Rightarrow r = \dfrac{7}{2\pi}$

Total surface area =

$2\pi (\dfrac{7}{2\pi})^{2} + 49\\\Rightarrow \dfrac{49}{2\pi}+49\\\Rightarrow 49(\dfrac{1}{2\pi}+1) cm^2$

Ratio of TSA: CSA is

$49(\dfrac{1}{2\pi}+1) cm^2 : 49 cm^2\\\Rightarrow (\dfrac{1}{2\pi}+1):1\\\Rightarrow (2\pi+1): 2\pi$

5 0

2 years ago

When multiplying two negative integers, what is the sign of the product?

geniusboy [140]

When mutiplying two negatives you will get a positive so answer A

6 0

3 years ago

Read 2 more answers

What is 4.66666666667 as a fraction

ss7ja [257]

Step-by-step explanation:

466666666667/100000000000

7 0

3 years ago