Please help me out!

Sarah is a computer engineer and manager and works for a software company. She receives a

daser333 [38]

Answer:

a) Number of projects in the first year = 90

b) Earnings in the twelfth year = $116500

Total money earned in 12 years = $969000

Step-by-step explanation:

Given that:

Number of projects done in fourth year = 129

Number of projects done in tenth year = 207

There is a fixed increase every year.

a) To find:

Number of projects done in the first year.

This problem is nothing but a case of arithmetic progression.

Let the first term i.e. number of projects done in first year = $a$

Given that:

$a_4=129\\a_{10}=207$

Formula for $n^{th}$ term of an Arithmetic Progression is given as:

$a_n=a+(n-1)d$

Where $d$ will represent the number of projects increased every year.

and $n$ is the year number.

$a_4=129=a+(4-1)d \\\Rightarrow 129=a+3d .....(1)\\a_{10}=207=a+(10-1)d \\\Rightarrow 207=a+9d .....(2)$

Subtracting (2) from (1):

$78 = 6d\\\Rightarrow d =13$

By equation (1):

$129 =a+3\times 13\\\Rightarrow a =129-39\\\Rightarrow a =90$

Number of projects in the first year = 90

b)

Number of projects in the twelfth year =

$a_{12} = a+11d\\\Rightarrow a_{12} = 90+11\times 13 =233$

Each project pays $500

Earnings in the twelfth year = 233 $\times$ 500 = $116500

Sum of an AP is given as:

$S_n=\dfrac{n}{2}(2a+(n-1)d)\\\Rightarrow S_{12}=\dfrac{12}{2}(2\times 90+(12-1)\times 13)\\\Rightarrow S_{12}=6\times 323\\\Rightarrow S_{12}=1938$

It gives us the total number of projects done in 12 years = 1938

Total money earned in 12 years = 500 $\times$ 1938 = $969000

8 0

3 years ago

the cost of four scarves and six hats is $52.00.the cost of two hats is $1 more then the cost of 1 scarf.how much does 1 scarf c

Elden [556K]

Please elaborate more on your question so I can help you

7 0

3 years ago

Anyone know the answer?

vodomira [7]

To solve your question, you add all of the measurements together, set them equal to 180, solve for x, and plug x back in for whichever angle they are asking for; in this case, they want angle R

7x + 12x + 20 + 20x - 35 = 180
39x - 15 = 180
39x = 180 + 15
39x = 195
x = 5

Angle R = 12x + 20
12(5) + 20
60 + 20
80

Option C is your answer.

5 0

3 years ago

Which correlation coefficient represents a moderate negative correlation? r = –0.04 r = –0.24 r = –0.64 r = –0.94

fomenos

The correlation coefficient is a number that indicates the direction

and closeness of points of a line of best of fit.

So it tells us two things.

It tells us the direction of the line of best fit

and it tells us the closeness of the points.

Usually, anything between -0.9 and -0.6 has a moderate negative correlation. If you look at this on a graph, you will notice that the points definitely resemble a line so we say it's moderate.

It will be a negative correlation because the slope is negative.

5 0

4 years ago

Read 2 more answers

Express 0.000216 in scientific notation

damaskus [11]

2.16 x 10 to the power of -4

3 0

3 years ago