Ask question

Ask question

All categories

2 years ago

7

A store owner paid $15 for a book. She marked up the price of the book by 40% to determine its selling price. What is the sellin

g price, in dollars, of the book?
\

1 answer:

densk [106]2 years ago

7 0

Answer:

the selling price is 21 dollars

You might be interested in

Gorge was able to solve 36 math problems in 15 muinutes. Urban was able to solve 42 math problems in 20 muinutes. Who was able t

MrRissso [65]

Answer:

Urban, 2.1 mins

Step-by-step explanation:

36 ÷ 3 = 2 (Gorge's)

42 ÷ 2 = 2.1 (Urban)

3 0

3 years ago

5. An airplane takes 4 hr to travel a distance of 4100 km. Another airplane travels at a speed

Mazyrski [523]

Answer:

4.969696 hours

Step-by-step explanation:

The distance traveled is shown through the following equations

Distance = velocity * time

This means that

4100=velocity*4

This means that ariplane 1 travles at 1025 km/hr

We can then subtract 200 from this to find that airplane two travels at a speed of 825 km/hr

Now we need to find how long it takes for that plane to travel 4100

So using the same equation

4100=825*time

Divison will tell us that the answer is around 4.9696 hours which is pretty much 5

7 0

3 years ago

Researchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research

kolbaska11 [484]

Complete Question

The complete question is shown on the first uploaded image

Answer:

a

Yes the researcher can conclude that the supplement has a significant effect on cognitive skill

b

$d = 0.5778$

c

The result of this hypothesis test shows that there is sufficient evidence to that the supplement had significant effect.The measure of effect size is large due to the large value of Cohen's d (0.5778 > 0.30 )

Step-by-step explanation:

From the question we are told that

The sample size is n=16

The sample mean is $M = 50.2$

The standard deviation is $\sigma = 9$

The population mean is $\mu = 45$

The level of significance is $\alpha = 0.05$

The null hypothesis is $H_o \mu =45$

The alternative hypothesis is $H_a \mu \ne 45$

Generally the test statistics is mathematically represented as

$z = \frac{M - \mu}{\frac{\sigma}{\sqrt{n} } }$

=> $z = \frac{50.2 - 45}{\frac{9}{\sqrt{16} } }$

=> $z = 2.31$

Generally the p-value is mathematically represented as

$p-value = 2 * P(Z > z )$

$p-value = 2 * P(Z > 2.31 )$

From the z-table

$P(Z > 2.31 ) = 0.010444$

=> $p-value = 2 * 0.010444$

=> $p-value = 0.021$

From the obtained values we see that $p-value < 0.05$

Decision Rule

Reject the null hypothesis

Conclusion

There is sufficient evidence to conclude that the supplement has a significant effect on the cognitive skill of elderly adults

Generally the Cohen's d for this study is mathematically represented as

$d = \frac{M - \mu}{\sigma }$

=> $d = \frac{50.2 -45}{9 }$

=> $d = 0.5778$

3 0

3 years ago

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

coldgirl [10]

Answer:

z = -0.4.

Step-by-step explanation:

Here's the formula for finding the z-score (a.k.a. standardized normal variable) of one measurement $x$ of a normal random variable $X \sim N(\mu,\; \sigma^{2})$ :

$\displaystyle z = \frac{x-\mu}{\sigma}$ ,

where

$z$ is the z-score of this measurement,
$x$ is the value of this measurement,
$\mu$ is the mean of the random normal variable, and
$\sigma$ is the standard deviation (the square root of variance) of the random normal variable.

Let the length of a trout in this lake be $X$ inches.

$X \sim N(30, \; 4.5^{2})$ .

$\mu = 30$ , and
$\sigma = 4.5$ .

For this measurement, $x = 28.2$ . Apply the formula to get the z-score:

$\displaystyle z = \frac{x - \mu}{\sigma} = \frac{28.2 - 30}{4.5} = -0.4$ .

5 0

3 years ago

PLS HELP ME<br> 362 divided 34<br> show your work

Darya [45]

10.6470588 there ya go ;)

4 0

2 years ago

Read 2 more answers