A factory uses 15 pounds of steel for every 18 pounds of copper. How much copper will the factory use for 2,700 pounds of steel?

frez [133]

SOLUTION:

Step 1:

From the given question, and comparing the scores in classes A and B

Step 2:

Question one, to know the class which had the better overall result on the exam;

(I) The scores in class A ranges from 65 to 100, while that of class B ranges from 60 to 90. This explains that class A had better results.

(ii) The median of the scores in class A is 85, while the median of the scores in class B is 75, this is another piece of supporting evidence that class A had better results.

Step 3:

Question two, to know the class which had greater variability in the results;

For a better understanding of this question, I need to explain the concept of variability in statistics.

Variability in statistics refers to the difference being exhibited by data points within a data set, as related to each other or as related to the mean. This can be expressed through the range, variance or standard deviation of a data set.

Step 4:

So we need to find the range of scores in each of the two classes and then compare, the class with the greater range has the greater variability.

The Range is the difference between the lowest and highest score (H - L), where H is the highest score and L is the lowest score.

Step 5:

Applying the formula for range stated in step 4;

For Class A; H = 100 and L = 65

For Class B; H = 90 and L = 60

The range for class A; H - L = 100 - 65 = 35

The range for class B; H - L = 90 - 60 = 30

By comparing the range of class A and that of B, it is clear that Class A had a greater range (variability)

CONCLUSION:

Class A had better overall results in the exam and greater variability in the results.

6 0

1 year ago

Which one of the following statements is true of perpendicular lines? A. They intersect to form an obtuse angle. B. They interse

quester [9]

They intersect at one point

6 0

3 years ago

Read 2 more answers

When an electric current passes through two resistors with resistance r1 and r2, connected in parallel, the combined resistance,

kondaur [170]

Answer:

a)

The combined resistance of a circuit consisting of two resistors in parallel is given by:

$\frac{1}{R}=\frac{1}{r_1}+\frac{1}{r_2}$

where

R is the combined resistance

$r_1, r_2$ are the two resistors

We can re-write the expression as follows:

$\frac{1}{R}=\frac{r_1+r_2}{r_1r_2}$

Or

$R=\frac{r_1 r_2}{r_1+r_2}$

In order to see if the function is increasing in r1, we calculate the derivative with respect to r1: if the derivative if > 0, then the function is increasing.

The derivative of R with respect to r1 is:

$\frac{dR}{dr_1}=\frac{r_2(r_1+r_2)-1(r_1r_2)}{(r_1+r_2)^2}=\frac{r_2^2}{(r_1+r_2)^2}$

We notice that the derivative is a fraction of two squared terms: therefore, both factors are positive, so the derivative is always positive, and this means that R is an increasing function of r1.

b)

To solve this part, we use again the expression for R written in part a:

$R=\frac{r_1 r_2}{r_1+r_2}$

We start by noticing that there is a limit on the allowed values for r1: in fact, r1 must be strictly positive,

$r_1>0$

So the interval of allowed values for r1 is

$0$

From part a), we also said that the function is increasing versus r1 over the whole domain. This means that if we consider a certain interval

a ≤ r1 ≤ b

The maximum of the function (R) will occur at the maximum value of r1 in this interval: so, at

$r_1=b$

6 0

3 years ago

Graph the function and analyze it for domain, range, continuity, increasing or decreaseing behavior, symmetry, boundedness, extr

Sunny_sXe [5.5K]

Answer:

$f(x) = 3 \cdot 0.2^x$

Step-by-step explanation:

$f(x) = 3 \cdot 0.2^x$

Domain of f: "What values of x can we plug into this equation?" This makes sense for all real numbers so the domain is $\mathbb{R}$

Range of f: "What values of f(x) can we get out of the function?" From the graph we see we can get any real number greater than 0 out of the function by choosing a suitable x-value in the domain. The range is therefore $(0, \infty)$ .

Continuity: Since the graph is one, unbroken curve (i.e. a curve that can be drawn in one movement without taking your pen off the paper). We see that "roughly speaking" the function is continuous.

Increasing or decreasing behaviour: For all x in the domain, as x increases, f(x) decreases. This means the function exhibits decreasing behaviour.

Symmetry: It is clear to see the graph of f(x) has no symmetry.

Boundedness: Looking at the graph we see it is unbounded above as when we choose negative values, the graph of f(x) explodes upwards exponentially. Choose a value of x, plug it in, next choose (x-1), plug this in and we observe $f(x-1) > f(x)$ for all x in the domain.

The function is however bounded below by 0: no value of x in the domain exists which satisfies $f(x) < 0$ .

Extrema: As far as I can tell, there are no turning points on the curve. (Is this what you mean by extrema?)

Asymptotes: Contrary to the curve's appearance, there are no vertical asymtotes for this curve. The negative-x portion of the curve is just growing so quickly it appears to look like an asymptote. There is a value of f(x) for all x<0. There is however a horizontal asymtote: $y=0$ .

End behaviour: As $x \rightarrow \infty, f(x) \rightarrow 0$ . As $x \rightarrow -\infty, f(x) \rightarrow +\infty$

5 0

3 years ago

A car dealer sends an email survey to all customers who bought two-door cars. The

Dvinal [7]

Answer: 150, 80

Step-by-step explanation:

6 0

3 years ago