All categories

4 years ago

Write the following proportion using colons. 7 is to 21 as 3 is to 9.

Mathematics

2 answers:

Lubov Fominskaja [6]4 years ago

7 0

The answer is 7:21 = 3:9.

Ksenya-84 [330]4 years ago

4 0

Answer:

Option A.

Step-by-step explanation:

There are two fraction given in this question and we have to write the proportion using colon.

Visually fractions $\frac{7}{21}$ and $\frac{3}{9}$ are different but when we simplify these fractions we get the actual relation between them.

We simplify $\frac{7}{21}$ first.

By dividing from 7 in the numerator and denominator we get

$\frac{\frac{7}{7}}{\frac{21}{7}}=\frac{1}{3}$

similarly we simplify the fraction $\frac{3}{9}$

By dividing numerator and denominator by 3

$\frac{\frac{3}{3} }{\frac{9}{3} }=\frac{1}{3}$

Now we can say that both the fractions are equal.

$\frac{7}{21}=\frac{3}{9}=\frac{1}{3}$

So the ratio will be 7 : 21 = 3 : 9

Option A. will be the answer.

You might be interested in

Giovanna can ride her bike 1.5 mi every 5 min. How many miles can she ride herbike in 24 min?

mote1985 [20]

7.2

if she can ride 1.5 mi in 5 min then she can ride 0.3 mi each minute, multiply 0.3 times 24 minutes and it gets 7.2 miles

4 0

3 years ago

Which equations have 5 as a solution

Ronch [10]

Answer:

u forgot to write the equations

4 0

3 years ago

Amy is cooking pancakes. The recipe calls for 5 1/4 cups of milk. She already has put in 2 1/10 cups. How many more cups does sh

AfilCa [17]

Answer:

Ok so lets break it down.

Step-by-step explanation:

5-2 = 3 now we have 1/4 and 1/10 10 divided by 4 = 2.5

So we can convert it then we have 2.5 out of ten.

then we add them up equals 3.5 out of ten.

Now we have 3.3.5 So now all we do is have to add 2.

7 0

3 years ago

Simplify 7-(x^2-3x+2)-2x(3x^2-x+1)

NeTakaya

Answer:

-6x^3+x^2+x+5

Step-by-step explanation:

distribute (multiply) the 7- into the first set of parenthesis. then distribute (multiply) the -2x into the second set of parenthesis.

3 0

3 years ago

Last year, a comprehensive report stated that 28% of businesses in the northeast of Ohio were considered highly profitable. This

Alik [6]

Answer:

$z=\frac{0.38 -0.28}{\sqrt{\frac{0.28(1-0.28)}{50}}}=1.575$

$p_v =2*P(z>1.575)=0.115$

So the p value obtained was a very high value and using the significance level given $\alpha=0.01$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of businesses were highly profitable is not significantly different from 0.28 or 28%.

Step-by-step explanation:

Data given and notation

n=50 represent the random sample taken

X=19 represent the businesses were highly profitable

$\hat p=\frac{19}{50}=0.38$ estimated proportion of businesses were highly profitable

$p_o=0.28$ is the value that we want to test

$\alpha=0.05$ represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

$p_v$ represent the p value (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the true proportion of businesses were highly profitable is different from 0.28 or no, the system of hypothesis is.:

Null hypothesis: $p=0.28$

Alternative hypothesis: $p \neq 0.28$

When we conduct a proportion test we need to use the z statistic, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

Calculate the statistic

Since we have all the info required we can replace in formula (1) like this:

$z=\frac{0.38 -0.28}{\sqrt{\frac{0.28(1-0.28)}{50}}}=1.575$

Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level provided $\alpha=0.01$ . The next step would be calculate the p value for this test.

Since is a bilateral test the p value would be:

$p_v =2*P(z>1.575)=0.115$

4 0

4 years ago