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3 years ago

10

The sum of the digits of a two-digit number is 15. Four times the tens digit plus twice the ones digit is 18. What is the number

?

1 answer:

kotegsom [21]3 years ago

6 0

Answer:

what does the fox say?

Step-by-step explanation:

nenenene

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Item 1 A discounted concert ticket costs $14.50 less than the original price p . You pay $53 for a discounted ticket. Write an e

VLD [36.1K]

Answer:

$53 + $14.50 = x

x = $67.50

Step-by-step explanation:

Let us assume the original price be x

It is given that

The discounted ticket is $53

And, the discounted concert ticket cost is $14.50 lower than the orginial price

So, the equation is

$53 + $14.50 = x

Now the x is

= $53 + $14.50

= $67.50

Hence, x denotes the original price of the ticket

We simply added the above two amounts

5 0

3 years ago

Kurt has $20. He spends $8. What percent of his money did Kurt spend?

wlad13 [49]

Answer:

40% Hope I helped

7 0

3 years ago

Read 2 more answers

The ratio of trucks to cars in a parking lot was 5 to 2. How many trucks were in the lot if there where 18 cars?

Elena L [17]

90 trucks- for every 2 cars there are 5 trucks

6 0

3 years ago

In an examination of purchasing patterns of shoppers, a sample of 16 shoppers revealed that they spent, on average, $54 per hour

Lesechka [4]

Answer:

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=54$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=21$ represent the sample standard deviation

n=16 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.90 or 90%, the value of $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

4 0

3 years ago

9. Gold miners in Alaska have found, on average, 12 ounces of gold per 1000 tons of dirt excavated with a standard deviation of

netineya [11]

Answer:

9.18% probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 12, \sigma = 3$

What is the probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated?

This is 1 subtracted by the pvalue of Z when X = 16. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{16 - 12}{3}$

$Z = 1.33$

$Z = 1.33$ has a pvalue of 0.9082

1 - 0.9082 = 0.0918

9.18% probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated

5 0

2 years ago