Is anyone good at math i need help with two review questions

⦁ Find the sum of the series . 15 sigma n=1, (2n-1) Show your work

sergejj [24]

Answer:

225

Step-by-step explanation:

The sum of this series is given by the formula:

$S_n=\frac{n}{2}[2a+(n-1)d]$

Where

S_n is the sum

a is the first term (we get this by plugging in n = 1 into "2n-1", we have 2(1) - 1 = 1)

n is the number of terms (the sum is defined for n = 1 to n = 15, so 15 terms)

d is the common different (the difference is successive terms. Here, 2nd term would be 2(2) - 1 = 3, and first term was 1, so d = 3 -1 = 2)

plugging in the info, we will get the sum:

$S_n=\frac{n}{2}[2a+(n-1)d]\\S_{15}=\frac{15}{2}[2(1)+(15-1)(2)]\\=225$

The sum is 225

4 0

2 years ago

There are two parking garages in beacon falls . Garage a charges $7.00 to park for the first 2 hours ,and each additional hour c

Julli [10]

Answer

Find out the number of hours when the cost of parking at both garages will be the same.

To prove

As given

There are two parking garages in beacon falls .

As given

Let us assume that the y is representing the cost of parking at both garages will be the same.

The total number of hours is represented by the x.

First case

Garage a charges $7.00 to park for the first 2 hours ,and each additional hour costs $3.00 .

As garage charges $7.00 for the first 2 hours so the remaning hours are (x -2)

Than the equation becomes

y = 3.00 (x -2) + 7.00

written in the simple form

y = 3x - 6 +7

y = 3x + 1

Second case

Garage b charges $3.25 per hour to park.

than the equation becomes

y = 3.25x

Compare both the equations

3x +1 = 3.25x

3.25x -3x = 1

.25x = 1

$x = \frac{1}{.25}$

x = 4hours

Therefore in the 4 hours the cost of parking at both garages will be the same.

3 0

2 years ago

Write an equation and identify the r value

aliya0001 [1]

Answer:

3)

i) $f(x)=1.1x+0.3$

ii) $r=1$

4)

i) $y=2.5825x+1.4369$

ii) $r=0.9823$

Step-by-step explanation:

We perform a simple linear regression analysis in megastat software to determine the line of best fit for both relations and their associated correlation coefficients.

3 0

2 years ago

The equation yˆ=20646·0.86x estimates the value of a brand of car x years after it was purchased new. Milo purchased this brand

zhannawk [14.2K]

Answer:

$195311

Step-by-step explanation:

Given the expression yˆ=20646*0.86x

Given that the number years 11

And x represent the number of years

Substituting x=11 in the expression for the cost we have

yˆ=20646*0.86(11)

yˆ=20646*9.46

yˆ=195311.16

From the analysis he purchased the car fro $195311

3 0

2 years ago

Fill in the missing information. Tim Worker is doing his budget. He discovers that the average miscellaneous expense is $45.00 w

nlexa [21]

Answer:

$P(38.6$

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

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

And replacing we got:

$z=\frac{38.6- 45}{16}= -0.4$

$z=\frac{57.8- 45}{16}= 0.8$

We can find the probability of interest using the normal standard table and with the following difference:

$P(-0.4$

Step-by-step explanation:

Let X the random variable who represent the expense and we assume the following parameters:

$\mu = 45, \sigma 16$

And for this case we want to find the percent of his expense between 38.6 and 57.8 so we want this probability:

$P(38.6$

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

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

And replacing we got:

$z=\frac{38.6- 45}{16}= -0.4$

$z=\frac{57.8- 45}{16}= 0.8$

We can find the probability of interest using the normal standard table and with the following difference:

$P(-0.4$

6 0

2 years ago