Please please please help me

Miss Croft made snack bags for the picnic that contain three types of snacks: packages of crackers, packages of cookies, and can

jek_recluse [69]

Answer: $1.25

Step-by-step explanation:

Let the cost of cracker be a.

Let the cost of cookies be b.

Let the cost of candy bars be c.

From the question,

6a + 6b + 6c = $21

8a + 5b + 10c = $26

5a + 4b + 7c = $18.50

To solve this, we first pick any two pairs of equation. This will be:

6a + 6b + 6c = $21 ....... i

8a + 5b + 10c = $26 ....... ii

Multiply equation i by 8

Multiply equation ii by 6

48a + 48b + 48c = $168 ....... iii

48a + 30b + 60c = $156 ....... iv

Subtract equation iv from iii

18b - 12c = 12

We then pick another two pairs

8a + 5b + 10c = $26

5a + 4b + 7c = $18.50

Multiply equation i by 5

Multiply equation ii by 8

40a + 25b + 50c = $130

40a + 32b + 56c = $148

Subtract the equations

-7b - 6c = -18

Then, solve the new equations formed

18b - 12c = 12 ....... v

-7b - 6c = -18 ....... vi

Multiply equation i by -7

Multiply equation ii by 18

-126b + 84c = -84

-126b - 108c = -324

Subtract the equations

192c = 240

c = 240/129

c = $1.25

From equation v, put the value of c

18b - 12c = 12

18b - 12($1.25) = 12

18b - $15 = $12

18b = $27

b = $27/18

b = $1.5

Since,

6a + 6b + 6c = $21

6a + 6($1.5) + 6($1.25) = $21

6a + $9 + $7.5 = $21

6a + $16.5 = $21

6a = $21 - $16.5

6a = $4.5

a = $4.5/6

a = $0.75

One candy bar cost $1.25

6 0

2 years ago

A researcher evaluates the significance of a multiple-regression equation and obtains an F-ratio with df = 2,24. How many partic

alisha [4.7K]

Answer:

N=27 participants

Step-by-step explanation:

Analysis of variance (ANOVA) "is used to analyze the differences among group means in a sample".

The sum of squares "is the sum of the square of variation, where variation is defined as the spread between each individual value and the grand mean"

When we conduct a multiple regression we want to know about the relationship between several independent or predictor variables and a dependent or criterion variable.

If we assume that we have $k$ independent variables and we have $j=1,\dots,j$ individuals, we can define the following formulas of variation:

$SS_{total}=\sum_{j=1}^n (y_j-\bar y)^2$

$SS_{regression}=SS_{model}=\sum_{j=1}^n (\hat y_{j}-\bar y)^2$

$SS_{error}=\sum_{j=1}^n (y_{j}-\hat y_j)^2$

And we have this property

$SST=SS_{regression}+SS_{error}$

The degrees of freedom for the model on this case is given by $df_{model}=df_{regression}=k=2$ where k =2 represent the number of variables.

The degrees of freedom for the error on this case is given by $df_{error}=N-k-1=24$ . Sinc we know k we can find N.

$N=24+k+1=24+2+1=27$

And the total degrees of freedom would be $df=N-1=27 -1 =26$

On this case the correct answer would be N=27 participants

6 0

2 years ago

A taut string of length 10 inches is plucked at the center. The vibration travels along the string at a constant rate of c inche

Mademuasel [1]

Answer:

The correct option is

$A. \ \dfrac{1}{c} \times \left | x - 5 \right | = 0.3$

Step-by-step explanation:

The parameters given are;

The length of the string = 10 inches

The speed or rate of travel of the wave = c inches per millisecond

The position on the string from the left-most end = x

The time duration of motion of the vibration to reach x= 0.3 milliseconds

The distance covered = Speed × Time = c×0.3

Given that the string is plucked at the middle, with the vibration travelling in both directions, the point after 0.3 millisecond is x where we have;

The location on the string where it is plucked = center of the string = 10/2 = 5 inches

Distance from point of the string being plucked (the center of the string) to the left-most end = 5 inches

Therefore, on the left side of the center of the string we have;

The distance from the location of the vibration x (measured from the left most end) to the center of the string = 5 - x = -(x -5)

On the right side of the center, the distance from x is -(5 - x) = x - 5

Therefore, the the equation that can be used to find the location of the vibration after 0.3 milliseconds is $\dfrac{1}{c} \times \left | x - 5 \right | = 0.3$ or $\left | x - 5 \right | = 0.3 \times c$ which gives the correct option as A

8 0

2 years ago

A home builder wants 5 5 acres of land split into 13 13 equal sections. Three of these expressions give the number of acres of l

stepladder [879]

Answer:

Check Explanation

Step-by-step explanation:

The options to be examined for the wrong one isn't presented, and it wasn't obtainable online, So, I'll exhaustively cover all the common possible answers!

5 acres of land. Acres is a unit of measurement that is most pecuilar to land. It is basically expressing the area of the land.

So, if 5 acres of land is to be divided into 13 sections with equal areas.

Each of the 13 land areas will have an area of (5/13) = 0.385 acre

1 acre = 4046.856 m²

5 acres = 20,234.28 m²

Each of the 13 land areas will have an area of (20234.28/13) = 1556.5 m²

1 acre = 43560 ft²

5 acres = 5 × 43560 = 217,800 ft²

Each of the 13 land areas will have an area of (217800/13) = 16,753.85 ft²

1 acre = 0.00156 square miles

5 acres = 5 × 0.00156 = 0.0078 square miles

Each of the 13 land areas will have an area of (0.0078/13) = 0.0006 square miles.

So, basically, whatever units one converts the area to, just divide the value by 13 and one obtains the area of each of the 13 portions of land that makes up the 5 acres.

Hope this Helps!!!

4 0

2 years ago

Read 2 more answers

Function f is a cosine function with period 8π, amplitude 3, and a local maximum at f(0) = –3. What is the equation of the midli

alisha [4.7K]

Answer:

y = 0

Step-by-step explanation:

Since there is no indication of a shift in the graph of f(x) = 3cos(-0.25x), then the midline must be the normal midline for a cosine or sine function which is: y = 0.

8 0

2 years ago

Read 2 more answers