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trapecia [35]
2 years ago
5

There are 60 students in a class. Among them,20 students are girls .Find the ratio ofa. Boys and total studentsb. girls and tota

l studentsc. boys and girlsd. girls and boys
Mathematics
1 answer:
valina [46]2 years ago
4 0

Answer:

Girls to boys = 1:2

Girls to students = 1:3

Boys to students = 2:3

Step-by-step explanation:

So, let's subtract the number of girls from the number of students in the class:

60 - 20 = 40

This means that for every 20 girls there are 40 boys in the ratio of girls to boys:

20:40

This can be simplified down by factoring, here we can divide by 20:

(20 ÷ 20) : (40 ÷ 20)

1:2

So the ratio of girls to boys is 1:2

The ratio of boys to students can be calculated via:

40:60

This can be simplified by dividing by 20 again:

(40 ÷ 20) : (60 ÷ 20)

2:3

So the ratio of boys to students is 2:3

The ratio of girls to students can be put in a ratio of:

20 : 60

This can be simplified down by dividing by 20:

(20 ÷ 20) : (60 ÷ 20)

1:3

So the ratio of girls to students is 1:3

Hope this helps!  

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It took a submarine 30 seconds to sink 225 feet, moving at a constant speed. The captain wants to know the submarine's speed.
Vladimir [108]

Answer:

Speed per second= 7.5 feet per second

Step-by-step explanation:

Giving the following information:

We have a distance (225 feet), and a time (30 seconds). Also, we know that the speed was constant.

<u>All we have to do is divide the distance by the time and determine the speed per second:</u>

Speed per second= distance / time

Speed per second= 225 / 30

Speed per second= 7.5 feet per second

5 0
3 years ago
Express in simplest radical form.<br> V40
Andrews [41]

Answer:

\huge\boxed{2 \sqrt{10}}

Step-by-step explanation:

When taking a square root and making it a radical, we need to list out it's factors and find which one we can take the square root of.

The factors of 40 are:

1, 2, 4, 5, 8, 10, 20, 40.

Out of these, we need to look for one that we can find the square root of.

We know that the square root of 4 is 2.

Therefore, we can make \sqrt{40} into \sqrt{4 \cdot 10}.

The square root of 4 is 2. Therefore, we can put that outside the radical.

2 \sqrt{10}.

Hope this helped!

7 0
3 years ago
What is minimal completion time for the activities in the graph below? In a complete sentence, explain how you got your answer
kupik [55]
The minimal completion time for the activities is the shortest possible time for all the activities to be finished. In doing this, we look at the path that would require the greatest amount of time. At the START node, we choose the path that would take the longest which is 7 days leading to ACTIVITY D. Next, we choose the path leading to ACTIVITY B which takes 5 days. Then, we move to ACTIVITY C taking 5 days and finally, reach the END which would take 6 days. So, the minimal completion time is:
7 + 5 + 5 + 6 = 23 days
6 0
3 years ago
Sarah claims that the thickness of the spearmint gum she produces is 7.5 one-hundredths of an inch. A quality control specialist
satela [25.4K]

Answer:

t=\frac{7.55-7.5}{\frac{0.103}{\sqrt{10}}}=1.539    

p_v =2*P(t_{(9)}>1.539)=0.158  

If we compare the p value and the significance level assumed \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to fail reject the null hypothesis.  

Step-by-step explanation:

Data given and notation  

Data: 7.65, 7.60, 7.65, 7.7, 7.55, 7.55, 7.4, 7.4, 7.5, 7.5

We can begin calculating the sample mean given by:

\bar X = \frac{\sum_{i=1}^n X_i}{n}

And the sample deviation given by:

s=\sart{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}

And we got:

\bar X=7.55 represent the sample mean

s=0.103 represent the sample standard deviation

n=10 sample size  

\mu_o =7.5 represent the value that we want to test

\alpha=0.05 represent the significance level for the hypothesis test.  

t would represent the statistic (variable of interest)  

p_v represent the p value for the test (variable of interest)  

State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the mean is equal to 7.5 or no, the system of hypothesis would be:  

Null hypothesis:\mu = 7.5  

Alternative hypothesis:\mu \neq 7.5  

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:  

t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}  (1)  

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".  

Calculate the statistic

We can replace in formula (1) the info given like this:  

t=\frac{7.55-7.5}{\frac{0.103}{\sqrt{10}}}=1.539    

P-value

The first step is calculate the degrees of freedom, on this case:  

df=n-1=10-1=9  

Since is a two sided test the p value would be:  

p_v =2*P(t_{(9)}>1.539)=0.158  

Conclusion  

If we compare the p value and the significance level assumed \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to fail reject the null hypothesis.  

3 0
3 years ago
REVIEWNy Long Division with Whole Numbers
dalvyx [7]

Answer

a= 15

b= 2

So, 647÷3= 215 + 2/3

Step-by-step explanation:

i just got it correct

7 0
3 years ago
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