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3 years ago

Divide 7/15 by 3/5 A. 7/9 B. 75/21 C. 21/75 D. 7/25

2 answers:

7 0

$\frac{7}{15} \div \frac{3}{5}=\frac{7}{15} \times \frac{5}{3}=\frac{7}{3 \times \not5} \times \frac{\not 5}{3}=\frac{7}{3 \times 3}=\frac{7}{9} \Rightarrow \hbox{the answer is A}$

hodyreva [135]3 years ago

4 0

7/15 ÷ 3/5 =
= 7/15 * 5/3 =
= 7/3 * 1/3 = (after simplifying)
= <u>7/9</u>

Correct answer: A

Just keep in mind that dividing one fraction by another fraction is as much as multiplying the same fraction by an inverse of the second one.

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How many more tons does a blue whale weigh than an African elephant

lapo4ka [179]

A blue whale weight = 200 short tons (400,000 pounds)
A african elephant weight = 3 tons (9,000 pounds)
And then you would minus the tons and get your answer
hope this helped :)

8 0

3 years ago

A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selec

VMariaS [17]

Answer:

$19.1-3.355\frac{1.5}{\sqrt{9}}=17.42$

$19.1+3.355\frac{1.5}{\sqrt{9}}=20.78$

And the best option would be:

C. [17.42,20.78]

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".

$\bar X=19.1$ represent the sample mean

$\mu$ population mean (variable of interest)

s=1.5 represent the sample standard deviation

n=9 represent the sample size

Solution to the problem

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:

$df=n-1=9-1=8$

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,8)".And we see that $t_{\alpha/2}=$

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

$19.1-3.355\frac{1.5}{\sqrt{9}}=17.42$

$19.1+3.355\frac{1.5}{\sqrt{9}}=20.78$

And the best option would be:

C. [17.42,20.78]

5 0

3 years ago

Help me someone:((!!!!!

LiRa [457]

Answer:

Hope this helps!

Step-by-step explanation:

2L + 3S = 83

4L + 8S = 197

Multiplies the top equation by -2.

-4L + -6S = -166

4l + 8S = 197

Adding them together...

2S = 31

S = 31/2 = 15.5

Plugging into the first equation:

2L + 3S = 83

2L + 3(15.5) = 83

2L + 46.5 = 83

2L = 83 - 46.5

2L = 36.5

L = 36.5/2 = 18.25

check:

2L + 3S = 2(18.25) + 3(15.5) = 36.5 + 46.5 = 83

4L + 8S = 4(18.25) + 8(15.5) = 73 + 124 = 197

The Large box weighs 18.25

The small box weighs 15.5

6 0

3 years ago

Sarah bought 18 boxes of 65 pens at $12 a box. She sold 378 of them at 3 for $1.00 and the rest at 4 for $1.00. Find her total p

KonstantinChe [14]

Answer:

$108

Step-by-step explanation:

1 box = $12

18 boxes = 12×18 = $216

Total = 18×65 = 1170 pens

Cost price, Cp = $216

3 = $1

378 = 378/3 = $126

1170-378= 792 pens remaining

4 = $1

792 = 792/4 = $198

Total selling price, sp = 126+198 = $324

Profit = Sp - Cp = 324 - 216 = $108

8 0

3 years ago

Can someone plz help me I’m being timed!!!!

nikklg [1K]

Answer:

49 and 58

Step-by-step explanation:

pls brainliest

7 0

3 years ago

Read 2 more answers