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2 years ago

6

Janet correctly answers 45 questions on her science test. There are 50 questions on the test. What percentage did she answer cor

rectly?

2 answers:

Hunter-Best [27]2 years ago

8 0

Answer:

90%

Step-by-step explanation:

45*2=90

50*2=100

90/100=90%

Hope this helped! brainliest would be great and good luck! :)

riadik2000 [5.3K]2 years ago

7 0

45/50 = 90/100 = 90%

You might be interested in

The ratio of money in Brian's wallet to Colin's wallet one day was 5:1. Brian spent £27 that day. Brian now had £3 less than Col

myrzilka [38]

Answer:

Brian had $30 initially.Brian had $30 initially.

Step-by-step explanation:

WE are given the following in the question:

Let Brian have x dollars and Colin have y dollars.

Ration of Brian's money to Colin's money is 5:1. This, we can write the equation:

$\dfrac{x}{y} = \dfrac{5}{1}\\\\x = 5y$

"Brian spent £27 that day. Brian now had £3 less than Colin."

Thus, we can write the equation:

$x-27 = y-3\\x-y = 24$

Solving the two equation by substitution, we get,

$x - y - 24\\5y - y = 24\\4y = 24\\y=6\\x = 5y =30$

Thus, Brian had $30 initially.

7 0

1 year ago

Consider the following random sample from a normal population: 14, 10, 13, 16, 12, 18, 15, and 11. What is the 95% confidence in

seraphim [82]

Answer:

$13.625-2.365\frac{2.669}{\sqrt{8}}=11.393$

$13.625+2.365\frac{2.669}{\sqrt{8}}=15.857$

So on this case the 95% confidence interval would be given by (11.393;15.857)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

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".

Data: 14, 10, 13, 16, 12, 18, 15, 11

We can calculate the sample mean and deviation with the following formulas:

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

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

$\bar X=13.625$ represent the sample mean

$\mu$ population mean (variable of interest)

s=2.669 represent the sample standard deviation

n=8 represent the sample size

Calculate the confidence interval

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=8-1=7$

Since the confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,7)".And we see that $t_{\alpha/2}=2.365$

Now we have everything in order to replace into formula (1):

$13.625-2.365\frac{2.669}{\sqrt{8}}=11.393$

$13.625+2.365\frac{2.669}{\sqrt{8}}=15.857$

So on this case the 95% confidence interval would be given by (11.393;15.857)

3 0

1 year ago

1. tentukan hasil dari 243⅔?

Vesnalui [34]

Penjelasan langkah demi langkah:

1)

$= 243^{\frac{2}{3} }\\= (\sqrt[3]{243})^2\\= 7^2\\= 49$

2) √32 +3√18-2√50

= √16*2 +3√9*2-2√25*2

= 4√2 + 3(3√2)-2(5√2)

= 4√2 + 9√2-10√2

= 13√2-10√2

= 3√2

3) 1000 ⅔×64⅙

$= (\sqrt[3]{1000}) ^2 \times (2^6)^{1/6} \\= 10^2 \times 2\\= 100 \times 2\\= 200$

4) 3/4+√2

$3/4+\sqrt{2} \\= \frac{3+4\sqrt{2} }{4 }$

5) 2√3×√18

= 2√3×√9*2

= 2√3×3√2

= (2*3)(√3*√2)

= 6√6

6) 12/3+√3

= 4+√3

7) √1000—2√40

= 10 -2 (√4*10)

= 10-2(2√10)

= 10 - 4√10

8) 2- ¹+3-¹

$= \frac{1}{2} + \frac{1}{3}\\ = \frac{3+2}{6}\\ = \frac{5}{6}$

9)

$\frac{5}{\sqrt{5} }\\ merasionalisasikan\\= \frac{5}{\sqrt{5} }\times \frac{\sqrt{5} }{\sqrt{5} }\\= \frac{5\sqrt{5} }{\sqrt{25} }\\= \frac{5\sqrt{5} }{5}\\ = \frac{\sqrt{5} }{1}$

Jika pernyataannya opsional, penyebutnya adalah 1

10) 2√3×√18

= 2√3×√9*2

= 2√3×3√2

= (2*3)(√3*√2)

= 6√6

7 0

2 years ago

There are 53 students on the Jackson Middle School basketball teams. The number of 8th graders is 15 fewer than three times the

pshichka [43]

Answer:

The number of 7th students on the Jackson Middle School basketball teams is 17 and the number of 8th students on the Jackson Middle School basketball teams is 36

Step-by-step explanation:

Let

x ----> the number of 7th students on the Jackson Middle School basketball teams

y ----> the number of 8th students on the Jackson Middle School basketball teams

we know that

There are 53 students on the Jackson Middle School basketball teams

so

$x+y=53$ -----> equation A

The number of 8th graders is 15 fewer than three times the number of 7th graders

so

$y=3x-15$ ----> equation B

substitute equation B in equation A

$x+(3x-15)=53$

solve for x

$x+3x=53+15\\4x=68\\x=17$

Find the value of y

$y=3(17)-15=36$

therefore

The number of 7th students on the Jackson Middle School basketball teams is 17 and the number of 8th students on the Jackson Middle School basketball teams is 36

6 0

1 year ago

Read 2 more answers

How do I solve w(x)=4x 5; find w(-8)?

Andrei [34K]

Plug -8 in for x: 4(-8) + 5 solve: -32 + 5 -27

4 0

2 years ago