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3 years ago

Solve for x. x - 5 = -15

Mathematics

2 answers:

garik1379 [7]3 years ago

6 0

Add 5 on both sides and it will give you ×=-10

Natasha2012 [34]3 years ago

6 0

x=-10 you just add 5 to both sides

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Dante invests $3,500 and learns 2% in simple interest each year assuming he makes no additional deposits or withdrawals how much

Rudik [331]

Answer:

answer in the picture

Step-by-step explanation:

8 0

2 years ago

At a large Midwestern university, a simple random sample of 100 entering freshmen in 1993 found that 20 of the sampled freshmen

guajiro [1.7K]

Answer:

The 90% confidence interval for the difference of proportions is (0.01775,0.18225).

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

p1 -> 1993

20 out of 100, so:

$p_1 = \frac{20}{100} = 0.2$

$s_1 = \sqrt{\frac{0.2*0.8}{100}} = 0.04$

p2 -> 1997

10 out of 100, so:

$p_2 = \frac{10}{100} = 0.1$

$s_2 = \sqrt{\frac{0.1*0.9}{100}} = 0.03$

Distribution of p1 – p2:

$p = p_1 - p_2 = 0.2 - 0.1 = 0.1$

$s = \sqrt{s_1^2+s_2^2} = \sqrt{0.04^2 + 0.03^2} = 0.05$

Confidence interval:

$p \pm zs$

In which

z is the z-score that has a p-value of $1 - \frac{\alpha}{2}$ .

90% confidence level

So $\alpha = 0.1$ , z is the value of Z that has a p-value of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

The lower bound of the interval is:

$p - zs = 0.1 - 1.645*0.05 = 0.01775
$

The upper bound of the interval is:

$p + zs = 0.1 + 1.645*0.05 = 0.18225
$

The 90% confidence interval for the difference of proportions is (0.01775,0.18225).

6 0

3 years ago

As a result of a cyclone, the price of bananas rose 85% to $9.99 per kg. How much did bananas cost before the cyclone?

Karo-lina-s [1.5K]

The original price was $8.49 :)

7 0

3 years ago

Answer all for points

IceJOKER [234]

Answer:

1. If we drink 8 glasses, we are drinking 2 L of water, so we are exceeding 1 L of water per day.

2. We need 100 sections.

I used metric conversion to convert km to meters.

3. 230 mL of lemonade per person

I used metric conversion to convert L to ML

Step-by-step explanation:

1. 250 mL = 1 glass

We are drinking 8 glasses

8 glasses * 250 ml/ 1 glass = 2000 mL

1 L = 1000 mL

2000 mL * 1 L/1000 mL =2 L

If we drink 8 glasses, we are drinking 2 L of water, so we are exceeding 1 L of water per day.

I used metric convertsion to convert mL to liters.

Guardrails sections to be 5m long

Road length that needs a guardrail is .5 km. We need to convert this to meters 1000 m = 1 km

.5km * 1000m / 1km = 500 meters

We have 500 meters that needs guardrails.

500 meters * 1 section/ 5 meters = 100 sections

We need 100 sections.

I used metric conversion to convert km to meters.

3. 6.9 L of lemonade to serve 30 people. We want to serve ml

Convert L to mL

1L = 1000 ML

6.9 L * 1000 ml/1L = 6900 mL

We need to divide 6900 Ml by 30 people

6900mL/30 people = 230 mL of lemonade per person

I used metric conversion to convert L to ML

5 0

3 years ago

If g(x) = -2x5 - 4, find g(2).

miskamm [114]

$g(x)+-2x^5-4$

Substitute the value of x = 2 to the equation:

$g(2)=-2\cdot2^5-4=-2\cdot32-4=-64-4=-68$

7 0

3 years ago