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goldfiish [28.3K]
3 years ago
14

Reco noticed that a nearby store was selling skateboards 25% off. The original price of the skateboard he wanted was $68. He bou

ght the skateboard at the sale price. How much was his discount?​
Mathematics
1 answer:
nexus9112 [7]3 years ago
6 0
He bought the skateboard at $51 it was $17 cheaper
You might be interested in
In a survey, the planning value for the population proportion is p* = 0.35. How large a sample should be taken to provide a 95%
lions [1.4K]

Answer:

n=\frac{0.35(1-0.35)}{(\frac{0.05}{1.96})^2}=349.59  

And rounded up we have that n=350  

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".  

p represent the real population proportion of interest

\aht p represent the estimated proportion for the sample

n is the sample size required (variable of interest)

z represent the critical value for the margin of error

Solution to the problem

The population proportion have the following distribution  

p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})  

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by \alpha=1-0.95=0.05 and \alpha/2 =0.025. And the critical value would be given by:  

z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96  

The margin of error for the proportion interval is given by this formula:  

ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}} (a)  

And on this case we have that ME =\pm 0.05 and we are interested in order to find the value of n, if we solve n from equation (a) we got:  

n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2} (b)

And replacing into equation (b) the values from part a we got:  

n=\frac{0.35(1-0.35)}{(\frac{0.05}{1.96})^2}=349.59  

And rounded up we have that n=350  

6 0
2 years ago
If synthetic division reveals a zero, why should we try that value again as a possible solution?
9966 [12]
Polynomials can have double roots, in fact they're pretty common. if you get a reasonable zero it costs very little time to try it again for a double root. answer is the second choice
6 0
2 years ago
Read 2 more answers
Is 0.000061 greater than 610,000<br>​
NeTakaya

Answer:

no.

Step-by-step explanation:

0.000061 is a decimal, and the number to the left of the decimal would be a whole number, which is 0. this means the number is less than one.. while 610,000 is a number jn the thousands, making it greater.

6 0
3 years ago
Read 2 more answers
It took Alice 6 5/6 hours to drive to her grandparents' house for Thanksgiving. On the way home, she ran into traffic and it too
salantis [7]

Time taken to drive to her grandparents house = 6 5/6  hours

We convert this mixed into improper fraction, we get = 41/6 hours

Time taken to drive to her grandparents house = 41/6 hours

Time taken to drive back = 8 2/9 hours

We convert this mixed into improper fraction, we get = 74/9 hours

Time taken to drive back = 74/9 hours

Difference between the two = 74/9 - 41/6  = (148-123)/18 = 25/18 hours = 1 7/18 hours

Therefore it took 1 7/18 hours longer to drive back.

6 0
3 years ago
john wants to fence in a portion of his backyard. the dimensions of the area are 12 1/2 yards long and 5 1/2 yards wide. how man
Troyanec [42]
12.5+12.5+5.5+5.5=36 there are 3 ft in a yard so 36*3=108ft
L+L+W+W= Area
3 0
3 years ago
Read 2 more answers
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