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3 years ago

Patricia scored 80% on a math test. She missed 4 problems. How many problems were on the test?

Mathematics

2 answers:

valina [46]3 years ago

7 0

Answer: There are 20 problems on the test.

Step-by-step explanation:

Since we have given that

Patricia scored 80% on a math test.

She missed 4 problems.

So, 20% of the math test is equal to 4 problems.

Let the total number of problems on the test be x

According to question,

$\frac{20}{100}\times x=4\\\\x=\frac{100}{20}\times 4\\\\x=20$

Hence, there are 20 problems on the test.

arsen [322]3 years ago

6 0

There would be exactly twenty problems on the test for her to be able to get 80%.
You know it can't be ten because then that would make it 60% not 80% but if you add the first number of the percentage (8) and multiply it by two it will get you 16 then if you add 4 to that that would make it 20 and 16/20 equals 80%

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..Urgent.. 600 students attend Ridgewood Junior High School. 10% of students bring their lunch to school everyday. How many stud

zysi [14]

Answer:

Number of student bring their lunch = 60

Step-by-step explanation:

Given:

Total number of student = 600

Student bring their lunch = 10%

Find:

Number of student bring their lunch

Computation:

Number of student bring their lunch = Total number of student x Student bring their lunch

Number of student bring their lunch = 600 x 10%

Number of student bring their lunch = 60

3 0

3 years ago

The local oil changing business is very busy on Saturday mornings and is considering expanding. A national study of similar busi

eimsori [14]

Answer:

$t=\frac{4.2-3.6}{\frac{1.4}{\sqrt{16}}}=1.714$

Reject the null hypothesis if the observed "t" value is less than -2.131 or higher than 2.131

Rejection Zone: $t_{calculated}$ or $t_{calculated}>2.131$

In our case since our calculated value is not on the rejection zone we don't have enough evidence to reject the null hypothesis at 5% of significance.

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=4.2$ represent the sample mean

$s=1.4$ represent the sample standard deviation

n=16 represent the sample selected

$\alpha=0.05$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is different from 3.6, the system of hypothesis would be:

Null hypothesis: $\mu = 3.6$

Alternative hypothesis: $\mu \neq 3.6$

If we analyze the size for the sample is < 30 and we 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:

$t=\frac{4.2-3.6}{\frac{1.4}{\sqrt{16}}}=1.714$

Critical values

On this case since we have a bilateral test we need to critical values. We need to use the t distribution with $df=n-1=16-1=15$ degrees of freedom. The value for $\alpha=0.05$ and $\alpha/2=0.025$ so we need to find on the t distribution with 15 degrees of freedom two values that accumulates 0.025 of the ara on each tail. We can use the following excel codes:

"=T.INV(0.025,15)" "=T.INV(1-0.025,15)"

And we got $t_{crit}=\pm 2.131$

So the decision on this case would be:

Reject the null hypothesis if the observed "t" value is less than -2.131 or higher than 2.131

Rejection Zone: $t_{calculated}$ or $t_{calculated}>2.131$

Conclusion

In our case since our calculated value is not on the rejection zone we don't have enough evidence to reject the null hypothesis at 5% of significance.

3 0

4 years ago

Find the value of x in the figure below:

KIM [24]

Answer:

let remaining angle in heptagon be a.

a+64=180(linear pair)

a=116

again

x+155+90+163+a+121°=720(sum of interior angle of hexagon is (6-2)×180°)

x+529+a=720

x+116=720-529

x=191-116=75

5 0

3 years ago

Using this formula l=A 1/2 what is the length of one side of a square with an area of 1,936 square kilometers? (A is the area of

Vera_Pavlovna [14]

c.)44 kilometers

Answer:

Solution given:

let

length =L

and

Area =A

Now

we have

Area [A]=1936 square kilometers

now

As we know that

Area of square :length *length

A=l*l

A=l²

Substituting value of A

1936=l²

doing square root on both side

$\sqrt{1936}=\sqrt{l²}$

we get

l= $\sqrt{2*2*2*2*11*11}$

l=2*2*11

l=44 kilometers

the length of one side of a square is 44 kilometers.

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