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3 years ago

7

I am a fraction whose Numerator and denominator are both prime numbers less than 20. If you were to increase each term by 1‚ I w

ould be equivalent to 1/2. What fraction am I?

1 answer:

11Alexandr11 [23.1K]3 years ago

6 0

Answer:

$\frac{2}{5}$ .

Step-by-step explanation:

Let the unknown fraction be $\frac{x}{y}$ ,

where, x and y both are prime numbers less than 20.

Now, it is given that adding 1 to both numerator and denominator will make the fraction $\frac{1}{2}$ .

Thus,

$\frac{x+1}{y+1}$ = $\frac{1}{2}$

2(x + 1) = y + 1

2x + 2 = y + 1

2x + 1 = y.

Clearly if x will be any odd number , two times x will be odd and adding 1 to it will result in even number and y should be even number , which is not possible as only even prime is 2.

Thus , x should be the even prime which is 2.

And y will be 5.

Thus the required fraction is $\frac{2}{5}$ .

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Please I really need help on this thank you

prisoha [69]

Answer:

D.) In the first 3 hours she had traveled a total of 200 miles

Step-by-step explanation:

By looking at the graph you can just go to the 3 hours mark and go upwards until you land on a whole number, in this case 200!

Hope I helped :)

8 0

3 years ago

Surveys tend to suffer from low response rates. Based on past experience, a researcher determines that the typical response rat

devlian [24]

Answer:

B.

Step-by-step explanation:

First let's define the different bias that exist:

Sampling bias: This bias occurs when the method used to get the sample favours one part of the population leaving another part of the population excluded.

Non response bias: This bias occurs when the people who do not answer the survey have different opinions from the ones who do.

Response bias: This bias occurs when the answer given to the survey does not reflect the true feelings of the person who responds.

Now back to the problem:

The researcher sent the survey to 2000 randomly selected e-mail addresses, she expects to get 20% of responses, meaning 400 people will answer the survey.

Given these conditions, we would expect the survey to be biased. We have approximately 1600 people who didn't answer the survey so it is possible that all these people who didn't answer have different opinions from the 400 who did (non response bias), given that the survey was done by email it could also happen that people do not tell the truth when asked about a topic (response bias), also, there would be sampling bias because the people who she selected have an email address so the people who don't use email get excluded from the survey (sampling bias)

6 0

3 years ago

Researchers wanted to study physical activity in children, so they gave 74 randomly chosen children a "FitBit" to recorded how m

luda_lava [24]

Answer:

Step-by-step explanation:

The estimated regression equation to predict the daily steps taken is:

Daily step= 6350.02 - 217.90BMI + 2702.12Grade_middle + 601.44BMI * Grade_middle

where Grade_middle=1 if the student is in middle school, and Grade_middle=0 if the student is in high school

b) The slope of BMI is -217.90. The negative value of the slope indicates that BMI and Daily steps taken move in opposite direction.

We can say that for 1 unit increase in the BMI, the predicted value of Daily Steps taken by the student decreases by 217.90, while keeping other variables unchanged.

c) The regression equation for middle school students can be obtained by setting Grade_middle=1

Daily step= 6350.02 - 217.90BMI + 2702.12 * 1 + 601.44BMI * 1

= 6350.02 - 217.90BMI + 2702.12 + 601.44BMI

= 9052.14 + 383.54BMI

Therefore, the slope of BMI on steps taken for students in middle school is 383.54

The regression equation for high school students can be obtained by setting Grade_middle=0

Daily Steps = 6350.02 - 217.90BMI + 2702.12 x 0 +601.44BMI*0 = 6350.02 - 217.90BMI

Therefore, the slope of BMI on steps taken for students in high school is -217.90

The model says that variables, the daily steps taken and the BMI of a middle school student are positively correlated (move in the same direction) and the daily steps taken and the BMI are negatively correlated (move in opposite direction) for a high school student. The above slopes say that for 1 unit increase in the BMI for students in middle school increases the predicted daily steps taken by 383.54 and for 1 unit increase in the BMI for students in high school decreases the predicted daily steps taken by 217.90

d) The predicted value of daily steps taken for a BMI=20 and Grade_middle=1 is

Daily Steps = 6350.02 – 217.90 x 20 + 2702.12 x1 +601.44 x 20 x 1 = 16722.94

The actual value of the daily steps taken by a middle school student with a BMI of 20 is 7000

The residual is calculated as

$\text{residual}=\text{Actual}-\text{predicted}=7000-16722.94=-9722.94$

Therefore, this student’s residual is -9722.94

7 0

3 years ago

I really need help guys can some one plz help me it's for 10 points

11111nata11111 [884]

Answer:

$\sqrt{8}----- 2units,2units$

$\sqrt{7} ------\sqrt{5}units,\sqrt{2}units$

$\sqrt{5}-------1unit,2units$

$3------2units, \sqrt{5}units$

Step-by-step explanation:

Use pythagorean's theorem to solve each pair individually.

The instructions say that you have the two sides (a and b) and you have to match it with their hypothenuse.

$Formula: c^2=a^2+b^2$

1. $a=\sqrt{5}, b=\sqrt{2}$

Plug this into the formula.

$c=\sqrt{(\sqrt{5} )^2+(\sqrt{2})^2 }$

The square here eliminates the roots.

$c=\sqrt{5+2}\\ c=\sqrt{7}$

2. $a=\sqrt{3}, b=4$

$c=\sqrt{(\sqrt{3} )^2+(4)^2}\\ c=\sqrt{3+16}\\ c=\sqrt{19}$

3. $a=2, b=\sqrt{5}$

$c=\sqrt{(2)^2+(\sqrt{5})^2 }\\ c=\sqrt{4+5}\\ c=\sqrt{9}\\ c=3$

4. $a=2, b=2$

$c=\sqrt{(2)^2+(2)^2}\\ c=\sqrt{4+4}\\ c=\sqrt{8}$

5. $a=1, b=2$

$c=\sqrt{(1)^2+(2)^2}\\ c=\sqrt{1+4}\\ c=\sqrt{5}$

7 0

3 years ago

Write an expression for the calculation double 2 and then add 5.

Mariana [72]

The expression is (2x2)+5

8 0

3 years ago