Multiple choice answers: 3 1/3 -1/3 -3

The smiths have two children. The sum of their ages is 23. The produce of their ages is 132. How old are the children?

kolezko [41]

For this case we propose a system of equations:

x: Let the variable representing the age of the first child of the Smiths

y: Let the variable representing the age of the second child of the Smiths

According to the data of the statement we have to:

$x + y = 23\\x * y = 132$

From the first equation we have to:

$x = 23-y$

We substitute in the second equation:

$(23-y) * y = 132\\23y-y ^ 2 = 132\\y ^ 2-23y + 132 = 0$

We find the solutions by factoring:

We look for two numbers that, when multiplied, result in 132 and when added, result in 23. These numbers are 11 and 12.

Thus, we have that the factorized equation is:

$(y-11) (y-12) = 0$

Thus, the solutions are: $y_ {1} = 11\\y_ {2} = 12$

So, we can take any of the solutions:

With $y = 11$

Then $x = 23-11 = 12$

Therefore, the ages of the children are 11 and 12 respectively.

Answer:

The ages of the children are 11 and 12 respectively.

6 0

3 years ago

A. What percent of data is greater than the 13th percentile?

Vladimir79 [104]

Answer:

a) Almost 87% of the distribution is greater than the 13th percentile.

b) This indicates that the distribution is symmetrical. This doesn't necessarily mean that the distribution is a normal distribution, but it is clear that the distribution is symmetrical.

c) This indicates that the distribution is rich skewed or positively skewed.

d) The third number that makes the mean 12 = 1.

e) The standard deviation is the square root of variance.

f) 3600 people that sat for the exam had a score at least as high as the 55th percentile's score.

Step-by-step explanation:

a) What percent of data is greater than the 13th percentile?

The percentile serves to group a data distribution into 100 equal spaces parts. It represents the value or the point below which a particular proportion of the distribution falls.

The 13th percentile thus represent a value or a point in the distribution that is higher than 13% of the distribution.

Hence, the percentage of data greater than the 13th percentile will be just about (100-13)%, almost 87% of the distribution will be greater than the 13th percentile.

b. If the mean, median, and mode for a data set are all the same, what can you conclude about the data’s distribution?

If all the three major measures of the centre of a distribution all coincide at the same point/value, it indicates that the distribution is symmetrical. This doesn't necessarily mean that the distribution is a normal distribution, but it is clear that the distribution is symmetrical.

c. If the mean is greater than the mode and median for a data set, what can you conclude about the data’s distribution?

The mean greater than the median and mode mean that distribution is rightly/positively skewed.

d. Mean of 3 numbers is 12. Two of them are 15 and 20. What is the third number?

The mean is the sum of variables divided by the number of variables

Mean = = (Σx)/N

x = each variable

Let the unknown third number be y

N = number of variables = 3

12 = (15 + 20 + y)/3

35 + y = 36

y = 36 - 35 = 1

e. What is the relationship between variance and standard deviation?

The variance is an average of the squared deviations from the mean.

The standard deviation is the square root of variance.

f. You scored in the 55th percentile on the GRE. If 8,000 people took the GRE, how many people had a score at least as high as your score?

Like I explained in (a), scoring 55th percentile mean that one has scored more than 55% of the people that sat for the exam.

So, the percentage of people that score as much as the 55th percentile will be the top (100-55)% of people thay sat for the exam.

45% of 8000 = 3600 people.

3600 people had a score at least as high as the 55th percentile's score.

Hope this Helps!!!

3 0

3 years ago

If a time series plot exhibits a horizontal pattern, then

gogolik [260]

Answer: C. there is still not enough evidence to conclude that the time series is stationary.

Step-by-step explanation: First thing to note for a time series plot is that it is required to select a suitable forecast method for the data set being considered.

A stationary time series means that the process generating the data set has a constant mean and the variations are constant over time. This means all evidence is present leading to the conclusion that the entire time series is stationary. A stationary time series thus exhibits an horizontal pattern which enables an appropriate forecast method to be selected for this type of pattern.

A horizontal pattern of a time series plot indicates that a data set fluctuates around a constant mean for a period of time. This period of time may however not be the entire time of the time series or take the entire data set into consideration and might just be a reflection of a portion of the time series hence why it can not be explicitly considered to be stationary. This means that a horizontal pattern can change into a seasonal or trending pattern if more variables/data are added over time.

For instance, a manufacturer sells a certain amount of products over a 10 week period and the resulting pattern of a time series plot is horizontal, then from the 11th week to the 15th week he gets a sharp and continuous increase in sales. This change in level will therefore change the time series plot from horizontal to trending making it more difficult to select a suitable forecast method.

6 0

3 years ago

A math thing 1. 3x + 2 = x + 4

aleksandrvk [35]

Answer:

X=1

This is correct due to basic algebra

3 0

3 years ago

Read 2 more answers

Which equation represents a proportional relationship?

notsponge [240]

Which equation represents a proportional relationship?

C. y=1/2x+3

5 0

3 years ago