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tekilochka [14]
3 years ago
10

A scientist needs to make 2 liters of saline solution (salt water), in which the salt

Mathematics
1 answer:
gulaghasi [49]3 years ago
5 0

Answer:

1.60 L of 10% solution

0.40 L of 35% solution

Step-by-step explanation:

If x = amount of 10% saline solution, and y = amount of 35% saline solution, then:

x + y = 2

0.10x + 0.35y = 0.15(2)

Solve with substitution:

0.10x + 0.35(2 − x) = 0.15(2)

0.10x + 0.70 − 0.35x = 0.30

0.40 = 0.25x

x = 1.60

y = 0.40

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7) 5x – 3y – 4z = 24<br> 5x + 3y + 5z = 27<br> 4x - 3y + 5z = 28
OLEGan [10]

Answer:

Step-by-step explanation:

8 0
3 years ago
PLEASE HELP WILL GIVE BRAINLIEST!!!!!!!!!!!!!!!!!!!!!!!!
STatiana [176]

Considering High School level question, answer can be written as:


A system of 2 linear equations is [two] dimensional. It is a graph of [two] lines. The solutions can be [unique] solution if the graph intersects. [No] solution if the lines are parallel - meaning they have the same slope, or [Infinitely many] solutions if they are the same line.


Explanation:

when two lines are drawn on a two-dimensional plane then there are only three possible cases:

Case1: lines will intersect

In that case you will get a unique solution at the intersection point.


Case2: lines are parallel but don't touch each other

In that case there will be no point which lies on both lines so No solution.


Case3: lines are overlapping.

In that case all the points lies on both lines so infinitely many solutions.


6 0
3 years ago
Suppose that an automobile manufacturer designed a radically new lightweight engine and wants to recommend the grade of gasoline
yawa3891 [41]

Answer:

B) 4.07

Step-by-step explanation:

First we need to calculate the mean of all the data, which is the same as the mean of the means of each grade of gasoline:

Regular    BelowRegular   Premium   SuperPremium

39.31             36.69                38.99             40.04

39.87            40.00                40.02             39.89

39.87            41.01                  39.99             39.93

X1⁻=39.68    X2⁻= 39.23       X3⁻= 39.66    X4⁻=  39.95

Xgrand⁻ = (39.68+39.23+39.66+39.95)/4 = 39.63

Next we need to calculate the sum of squares within the group (SSW) and the sum of squares between the groups (SSB), and the respective degrees of freedom):

SSW = [ (39.31-39.68)² + (39.87-39.68)² + (39.87-39.68)² ] + [ (36.69-39.23)² + (40.00-39.23)² + (41.01-39.23)² ] + [ (38.99-39.66)² + (40.02-39.66)² + (39.99-39.66)² ] + [ (40.04-39.95)² + (39.89-39.95)² + (39.93-39.95)² ] = [0.2091] + [10.2129] + [0.6874] + [0.0121] = 11.12

SSW =  11.12

Degrees of freedom in this case is calculated by m(n-1), with m being the number of grades of gasoline (4) and n being the number of trial results for each one (3), so we would have 4(3-1) = 8 degrees of freedom

SSB = [ (39.68-39.63)² + (39.68-39.63)² + (39.68-39.63)²] + [ (39.23-39.63)² + (39.23-39.63)² + (39.23-39.63)² ] + [ (39.66-39.63)² + (39.66-39.63)² + (39.66-39.63)² ] + [ (39.95-39.63)² + (39.95-39.63)² +(39.95-39.63)² ] = [0.0075] + [0.48] + [0.0027] + [0.3072] = 0.7974

SSB =  0.80

For this case, the degrees of freedom are m-1, so we would have 4-1 = 3 degrees of freedom

Now we can establish the hypothesis for the test:

H0: μ1 = μ2 = μ3 = μ4

The null hypothesis states that the means of miles per gallon for each fuel are the same, indicating that the drade of gasoline does not make a difference, therefore our alternative hypothesis will be:

H1: the grade of gasoline does makes a difference

We will use the F statistic to test the hypothesis, which is calculated like follows:

F - statistic = (SSB/m-1) / (SSW/m(n-1)) = (0.80/3) / (11.12/8) = 0.19

We know that the level of significance we are using is α = 0.05, so to find the critical value F we need to look at some table of critical values for the F distribution for the 0.05 significance level (like the attached image). Then we just need to look fot the value that is located in the intersection between the degrees of freedom we have in the numerator (horizontal) and the denominator (vertical) of the statistic (3 and 8). That critical value is:

Fc = 4.07

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3 years ago
Translate this sentence into an equation.
lana [24]

Answer:

c+20=72

Step-by-step explanation:

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3 years ago
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Strike441 [17]

Answer:

A rectangle with a width of 5 inches and a length of 7 inches.

A rectangle with a width of 4 inches and a length of 6 inches

Step-by-step explanation:

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3 years ago
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