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3 years ago

A simple random sample of 12 iPhone's being sold over the Internet had the

Mathematics

1 answer:

bearhunter [10]3 years ago

7 0

Answer:

The upper bound is 399.5

Step-by-step explanation:

Let's start by calculating the mean value of the distribution as the addition of all values given divided by 12:

Average = 289.75.

If the standard deviation is 56, then the upper bound in 95% the confidence interval for the mean price of the phones is going to be given by the mean value added to 56 times 1.96 (since 95% of the population is withing 1.96 times the standard deviation)

That is: 289.75 + 56 * 1.96 = 399.51

which rounded to one decimal place gives: 399.5

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Root 8-3 root 32 + 4 root 50

Bess [88]

Answer:

$10\sqrt{2}$

Step-by-step explanation:

$\sqrt{8} -3\sqrt{32} +4\sqrt{50}$

We can try to simplify first.

$2\sqrt{2}-12\sqrt{2} +20\sqrt{2}$

Now we can combine the like terms:

$= 10\sqrt{2}$

hope this helped! :)

3 0

1 year ago

6 - 8a + 5a - 35

Fittoniya [83]

Ok, so after you do -8a+5a, you also have to do 6 -35, getting the equation
-29-3a

7 0

2 years ago

I need help asappppppp!!!!!!!!!

trapecia [35]

An=A(n-1)-5.9

The next two are -18.5 and -24.4

You subtract 5.9 from the previous number to get the new number

7 0

2 years ago

One of your employees is bidding on a carpet installation job. They estimate that it will take 3 hours to install 12 square yard

Charra [1.4K]

Answer:

No, the bid is not correct.

Step-by-step explanation:

One of your employees is bidding on a carpet installation job.

They estimate that it will take 3 hours to install 12 square yards of carpeting.

we know that 1 square yard= 9 square foot.

12 square yard= 12×9 square foot=108 square foot

i.e. it takes 3 hours to carpet 108 square foot.

Hence time taken to carpet 1 square foot= $\dfrac{3}{108}$ hour

Now the dimension of room is:

11' 6"× 12' 9" i.e. we convert both the units to foot as:

1 foot= 12 inch

11'6"=11+(6/12)=11.5 foot.

and 12'9"=12+(9/12)=12.75 foot.

Hence, dimension of room=11.5 foot×12.75 foot

Hence area of room=11.5×12.75=146.625 square foot.

Time to carpet 146.625 square foot=

$\dfrac{3}{108}\times 146.625$ hour

=4.0729 hour

But it is given that it takes 12.3 hours to install the carpet.

Hence, the calculations were wrong.

6 0

2 years ago

Read 2 more answers

<img src="https://tex.z-dn.net/?f=%5Cfrac%7Ba%5E%7B2%7D-1%7D%7B2-5a%7D%20times%20%5Cfrac%7B15a-6%7D%7Ba%5E%7B2%7D%2B5a-6%7D" id=

stepan [7]

$\bf \cfrac{a^2-1}{2-5a}\times \cfrac{15-6}{a^2+5a-6}\\\\
-----------------------------\\\\
recall\quad \textit{difference of squares}
\\ \quad \\
(a-b)(a+b) = a^2-b^2\qquad \qquad 
a^2-b^2 = (a-b)(a+b)\\\\
thus\quad a^2-1\iff a^2-1^2\implies (a-1)(a+1)
\\\\\\
now\quad a^2+5a-6\implies (a+6)(a-1)\\\\
-----------------------------\\\\
thus
\\\\\\
\cfrac{a^2-1}{2-5a}\times \cfrac{15-6}{a^2+5a-6}\implies \cfrac{(a-1)(a+1)}{2-5a}\times \cfrac{3(5a-2)}{(a+6)(a-1)}\\\\
-----------------------------\\\\
$

$\bf now\quad 3(5a-2) \iff -3(2-5a)\\\\
-----------------------------\\\\
thus
\\\\\\
\cfrac{\underline{(a-1)}(a+1)}{\underline{2-5a}}\times \cfrac{-3\underline{(2-5a)}}{(a+6)\underline{(a-1)}}\implies \cfrac{-3(a+1)}{a+6}$

6 0

3 years ago