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3 years ago

Sara tried to evaluate 21 : 7 x 8 step-by-step

Mathematics

1 answer:

nlexa [21]3 years ago

6 0

Answer: Sara multiplied by 3 when she should have multiplied by 8.

Step-by-step explanation:

21 : 7*8

7*8 = 56

21 : 56

The simplest form of this ratio is 3 : 8

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How do you write four million, six hundred five thousand in standard form

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3 years ago

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Sam shot the basketball 15 times. 40% of his shots were made. How many shots did Sam make?

love history [14]

Answer:

Step-by-step explanation:

40% is equal to 40/100

He made 40% of 15 shots so you miltiply 15 by 40/100 which is equal to 6.

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2 years ago

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Determine the time needed to deliver 72 papers at a rate of 9 papers in 18 minuets

monitta

Hey there,

Question : Determine the time needed to deliver 72 papers at a rate of 9 papers in 18 minuets

Answer :
9 papers = 18 min
1 paper = 18 / 9
= 2 min
72 papers = 2 x 72
= 144 mins

Hope this helps :))

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3 years ago

I have a question that says " jada has read 3/5 of a book. She has read 75 pages so far. How many pages are in the whole book?"

jok3333 [9.3K]

Answer and Step-by-step explanation:

To solve, we would multiply by the reciprocal of the portion Jada has read, and multiply that number to 75.

The reciprocal means the the value, but flipped, so $\frac{3}{5}$ will become $\frac{5}{3}$ .

Now we do 75 times $\frac{5}{3}$ /

$\frac{75 * 5}{3} \\\\\\\\\frac{375}{3} \\\\\\\\125$

So, there are 125 total pages in the book.

#teamtrees #PAW (Plant And Water)

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3 years ago

A company surveyed 2400 men where 1248 of the men identified themselves as the primary grocery shopper in their household. a) E

polet [3.4K]

Answer:

a) With a confidence level of 98%, the percentage of all males who identify themselves as the primary grocery shopper are between 0.4962 and 0.5438.

b) The lower limit of the confidence interval is higher that 0.43, so if he conduct a hypothesis test, he will find that the data shows evidence to said that the fraction is higher than 43%.

c) $\alpha =1-0.98=0.02$

Step-by-step explanation:

If np' and n(1-p') are higher than 5, a confidence interval for the proportion is calculated as:

$p'-z_{\alpha/2}\sqrt{\frac{p'(1-p')}{n} }\leq p\leq p'+z_{\alpha/2}\sqrt{\frac{p'(1-p')}{n} }$

Where p' is the proportion of the sample, n is the size of the sample, p is the proportion of the population and $z_{\alpha/2}$ is the z-value that let a probability of $\alpha/2$ on the right tail.

Then, a 98% confidence interval for the percentage of all males who identify themselves as the primary grocery shopper can be calculated replacing p' by 0.52, n by 2400, $\alpha$ by 0.02 and $z_{\alpha/2}$ by 2.33

Where p' and $\alpha$ are calculated as:

$p' = \frac{1248}{2400}=0.52\\\alpha =1-0.98=0.02$

So, replacing the values we get:

$0.52-2.33\sqrt{\frac{0.52(1-0.52)}{2400} }\leq p\leq 0.52+2.33\sqrt{\frac{0.52(1-0.52)}{2400} }\\0.52-0.0238\leq p\leq 0.52+0.0238\\0.4962\leq p\leq 0.5438$

With a confidence level of 98%, the percentage of all males who identify themselves as the primary grocery shopper are between 0.4962 and 0.5438.

The lower limit of the confidence interval is higher that 0.43, so if he conduct a hypothesis test, he will find that the data shows evidence to said that the fraction is higher than 43%.

Finally, the level of significance is the probability to reject the null hypothesis given that the null hypothesis is true. It is also the complement of the level of confidence. So, if we create a 98% confidence interval, the level of confidence $1-\alpha$ is equal to 98%

It means the the level of significance $\alpha$ is:

$\alpha =1-0.98=0.02$

4 0

3 years ago