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3 years ago

Martina walked 3/4 of a mile in 1/5 of an hour. At this rate , how far can Martina walk in one hour?

1 answer:

4 0

Hey there!

To make this easier, we need to transform the numbers in decimal

3/4 = 0.75

1/5 = 0.2

So Martina walks 0.75 miles in 0.2 hour. They want us to find how far will she wake in 1 hour.

So we say:

0.75......>0.2 hr
x...........1 hr

Cross multiply

0.2 * x = 1 * 0.75

0.2x = 0.75

x = 0.75/0.2

x = 3.75

Martina will work 3.75 miles in one hour.

I hope this helps!

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Emissions of sulfur dioxide by industry sett off chemical changes in the atmosphere that result in "acid rain". The acidity of l

horsena [70]

Answer:

Case n =5

$z=\frac{4.8-5}{\frac{0.5}{\sqrt{5}}}=-0.894$

Case n =15

$z=\frac{4.8-5}{\frac{0.5}{\sqrt{15}}}=-1.549$

Case n = 40

$z=\frac{4.8-5}{\frac{0.5}{\sqrt{40}}}=-2.530$

P value

Case n =5

$p_v =P(z$

Case n =15

$p_v =P(z$

Case n =40

$p_v =P(z$

Step-by-step explanation:

Data given and notation

$\bar X=4.8$ represent the sample mean

$\sigma=0.5$ represent the population standard deviation

$n$ sample size

$\mu_o =5$ represent the value that we want to test

$\alpha$ represent the significance level for the hypothesis test.

z would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is lower than 5, the system of hypothesis would be:

Null hypothesis: $\mu \geq 5$

Alternative hypothesis: $\mu < 5$

Since we know the population deviation, is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

Case n =5

$z=\frac{4.8-5}{\frac{0.5}{\sqrt{5}}}=-0.894$

Case n =15

$z=\frac{4.8-5}{\frac{0.5}{\sqrt{15}}}=-1.549$

Case n = 40

$z=\frac{4.8-5}{\frac{0.5}{\sqrt{40}}}=-2.530$

P-value

Since is a left tailed test the p value would be:

Case n =5

$p_v =P(z$

Case n =15

$p_v =P(z$

Case n =40

$p_v =P(z$

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4 years ago

Two addends

nataly862011 [7]

Answer:

Step-by-step explanation:

18+6+4=28

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3 years ago

What is the answer to 4|x-1|=12

STatiana [176]

Answer:

(4,0) and (- 2,0): Answer

Step-by-step explanation:

Absolute value questions have two essential steps.

1. Solve the equation as it is written.

2. Solve it changing the sign of the right hand side. I will include a graph to confirm my answer

4*abs(x - 1) = 12 Divide by 4

abs(x - 1) = 12/4
abs(x - 1) = 3 Equate this to 3
x - 1 = 3 Add 1 to both sides
x - 1 + 1 = 3 + 1 Combine
x = 4

4*abs(x - 1) = - 12 Divide by 4

abs(x - 1) = - 12/4
abs(x - 1) = - 3
x - 1 = - 3 Add 1 to both sides
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So this has 2 answers

(4,0) and (- 2,0)

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3 years ago

Geometry help needed!

lilavasa [31]

Answer:

13.76

Step-by-step explanation:

Area of the whole

The area of the whole = s^2 (the firgure is a square

s = 8

Area of the whole = 8^2 = 64

Area of the unshaded part

The 2 half circles = 1 whole circle

The radius of the 1/2 circle = 4 (eight has been cut in half)

Area of two half circles = 2* (pi r^2/2)

Area of two half circles = 2 * (pi 4^2/2)

area of two half circles = 16*pi

Area of the shaded area

Area of the shaded area = area of the whole - area of the unshaded area

Area of the shaded area = 64 - 16*pi

Area of the shaded area = 64 - 3.14*16 = 13.76

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221,000,000,000,000,000,000 in scientific notation

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2.21 x 10^17 and the answer is 2.21e+17

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