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3 years ago

PLEASE HELP I NEED THE ANSWER BY 3PM EST ON 3/3/21

Mathematics

1 answer:

Andreyy893 years ago

6 0

9514 1404 393

Explanation:

To find the time, substitute the height for h(t), then solve the quadratic equation for t.

___

To solve the equation, you subtract the height from both sides, then use the quadratic formula. In generic terms, this looks like ...

-16t^2 +32t -h = 0

t = (-32±√(32^2 -4(-16)(-h)))/(2(-16))

t = (-32 ± √(1024-64h))/-32

t = 1 ± √(1 -h/16)

For h = 10 ft, the times are ...

t = 1 ± √(3/8) ≈ {0.388, 1.612} . . . . seconds

Using the quadratic formula is not the only way to solve a quadratic. One of my favorite methods is using a graphing calculator.

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Last year Jo paid £245 for her car insurance. This year she has to pay £883 for her car insurance. Work out the percentage incre

S_A_V [24]

Answer:

260%

Step-by-step explanation:

To solve how much the percentage increase cost of Jo's car insurance is, we first need to list down our variables.

1st year = £245

2nd year = £883

First off, we need to find the difference of the two.

Increase = £883 - £245

Increase = £638

Now to find the percentage increase, we take our increase and divide it by our 1st year's payment and multiply it by 100.

Percentage increase = $\dfrac{638}{245}*100$

Percentage increase = $2.60*100$

Percentage increase = 260%

So the percentage increase of last years payment to this years payment is 260%.

8 0

4 years ago

A researcher surveyed 150 high school students and found that 68% played a musical insturment. What would be a reasonable range

maria [59]

Answer:

The reasonable range for the population mean is (61%, 75%).

Step-by-step explanation:

The interval estimate of a population parameter is an interval of values that consist of the values within which the true value of the parameter lies with a certain probability.

The mean of the sampling distribution of sample proportion is, $\hat p$ .

One of the best interval estimate of population proportion is the 95% confidence interval for proportion,

$CI=\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}$

Given:

n = 150

$\hat p$ = 0.68

The critical value of <em>z</em> for 95% confidence level is:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

Compute the 95% confidence interval for proportion as follows:

$CI=\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}$

$=0.68\pm1.96\sqrt{\frac{0.68(1-0.68)}{150}}\\\\=0.68\pm 0.0747\\\\=(0.6053, 0.7547)\\\\\approx (0.61, 0.75)$

Thus, the reasonable range for the population mean is (61%, 75%).

5 0

4 years ago

Monica says,"if 4 bottles cost $10, then 2 bottles cost $5 + $20." Is Monica correct? Explain

Igoryamba

Answer:

Monica is not correct.

Step-by-step explanation:

First of all, if 4 bottles only cost $4, then how would only 2 cost more? (She said the two bottles would be $25, which doesn’t make sense.)

8 0

3 years ago

A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by gi

GuDViN [60]

The time that rocket will hit the ground, to the nearest 100th of second is 10.43 seconds

Given the equation representing the height reached by a rocket as:

$y = -16x^2 + 157x + 104$

The rocket will hit the ground when y = 0. Substituting y = 0 into the expression to get x;

$0 = -16x^2 + 157x + 104\\16x^2 - 157x - 104 = 0\\$

On factorizing:

x = 10.43 seconds

Hence the time that rocket will hit the ground, to the nearest 100th of second is 10.43 seconds

Learn more here: brainly.com/question/14479223

6 0

3 years ago

The 95% confidence interval for a population mean (context unknown and irrelevant) turns out to be (428, 510). What is E?

Elina [12.6K]

The 95% confidence interval for a population mean has a margin of error (E) of 41

The confidence interval for a population mean is given by:

Confidence interval = μ ± E = (μ - E, μ + E)

Where μ is the mean and E is the margin of error.

Since the confidence interval is (428, 510), hence:

μ - E = 428 (1)

μ + E = 510 (2)

Subtracting equation 1 from equation 2:

2E = 82

E = 41

μ - E = 428

μ -41 = 428

μ = 469

Hence the margin of error (E) is 41

Find out more at: brainly.com/question/10501147

6 0

3 years ago