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4 years ago

Two software companies are planning to launch a learning application on the same day.

Mathematics

1 answer:

Ulleksa [173]4 years ago

5 0

We have that we are given 4 formulas for the products; there are split in 2, one for each company and they are also split in 2 on whether they are predictions or date. We need to substitute in x=4 days for all of them to calculate the value after 4 days after the launch (initial day counts for x=0).
For company A, the actual average downloads per day were: for x=0 (day 1), x=1, x=2, x=3, x-4:
f(0)=450, f(1)=562.5, f(2)=703, f(3)=879, f(4)=1099
To find the average download per days, we have that we divide the final downloads f(4) by the number of days, 4. This yields 275 downloads per day.
For the prediction formula f(x)=400*1.5^x, if we substitute x=4 we get 2025 downloads. This yields on average 506 downloads per day.
Thus, the difference is 231 downloads per day and we have a decrease in the data (from predicted to actual downloads).

For company B, the same procedure for the actual data yields: g(4)=2621 downloads after 4 days, hence 655 downloads on average; the prediction data yields 500*1.4^4=1921 and on average 480 downloads per day; the difference is around 175 (174 due to rounding errors) downloads per day and it is still a decrease (predictions are lower).

Thus, company B was more accurate.

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X^2+y^2=25 find the distance of point (x,y) from origin

storchak [24]

Answer:

Step-by-step explanation:

The radius is 5.

All I do was think of the center-radius form a circle

(x-h)^2+(y-k)^2=r^2

x^2 + y^2 =25

(x-0)^2+(y-0)^2=5^2

The center is (0,0) and the radius is 5.

So a point on the circle (x,y) has a distance of 5 from the center

and the center's case here is (0,0).

3 0

3 years ago

Simplify. 5(x - y) - (x - y) a. x - y b. x y c. 4x - 4y d. 4x 4y

chubhunter [2.5K]

C is the answer hope this helps.

5 0

4 years ago

A random sample of 36 observations has been drawn from a normal distribution with mean 50 and standard deviation 12. Find the pr

Gre4nikov [31]

Answer:

$z= \frac{47 -50}{\frac{12}{\sqrt{36}}}=-1.5$

$z= \frac{53 -50}{\frac{12}{\sqrt{36}}}=1.5$

And using a calculator, excel ir the normal standard table we have that:

$P(47 \leq \bar X \leq 53) =P(-1.5 \leq Z \leq 1.5)$

And we can calculate the probability like this: $P(-1.5 \leq Z \leq 1.5) = P(z$ Step-by-step explanation:

A random sample of 36 observations has been drawn from a normal distribution with mean 50 and standard deviation 12. Find the probability that the sample mean is in the interval 47<=X<53. Is the assumption of normality important. Why?

Previous concepts

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".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:

$X \sim N(50,12)$

Where $\mu=50$ and $\sigma=12$

Since the distribution for X is normal then we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

We can find the probability required like this:

$z= \frac{47 -50}{\frac{12}{\sqrt{36}}}=-1.5$

$z= \frac{53 -50}{\frac{12}{\sqrt{36}}}=1.5$

And using a calculator, excel ir the normal standard table we have that:

$P(47 \leq \bar X \leq 53) =P(-1.5 \leq Z \leq 1.5)$

And we can calculate the probability like this:

$P(-1.5 \leq Z \leq 1.5) = P(z$

4 0

3 years ago

One integer is 7 more than another. Their product is 98. Find the integers,

ipn [44]

Answer:

- 14, - 7 or 7, 14

Step-by-step explanation:

Let the the two integers be x and (x + 7)

$\therefore \: x(x + 7) = 98 \\ {x}^{2} + 7x - 98 = 0 \\ {x}^{2} + 14x - 7x - 98 = 0 \\ x(x + 14) - 7(x + 14) = 0 \\ (x + 14)(x - 7) = 0 \\ (x + 14) = 0 \: or \: (x - 7) = 0 \\ x = - 14 \: or \: x = 7 \\ \\ when \: x = - 14 \\ x + 7 = - 14 + 7 = - 7 \\ \\ when \: x = 7 \\ x + 7 = 7 + 7 = 14 \\$

Hence the required integers are - 14, - 7 or 7, 14

5 0

4 years ago

What value of x is in the solution set of 8x - 6 > 12 + 2x? -1 e Of 3 5

vivado [14]

Answer:

x > 3

Step-by-step explanation:

Step 1: Isolate x

6x -6 > 12

6x > 18

Step 2: Divide

x > 3

7 0

4 years ago