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Dmitry_Shevchenko [17]

3 years ago

11

If 3/4 of a ton of sand covers 2/5 of a playground, how many tons of sand are required to cover the entire playground?

1 answer:

saw5 [17]3 years ago

5 0

3t/4=2p/5 solve for p

p=15t/8

p=1.875 tons of sand

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One uranium atom has a mass of 3.95 x 10^-22 grams.

creativ13 [48]

Remember
(ab)/(cd)=(a/c)(b/d)
and
$\frac{x^n}{x^m}=x^{n-m}$

1kg=1000g=1*10^3g
hmm, I estimate, 4 of them

x=number of attoms
mass of 1 times x=1*10^3
3.95*10^-22 times x=1*10^3
divide both sides by 3.95*10^-22
x= $\frac{1*10^3}{3.95*10^{-22}}= (\frac{1}{3.95} )( \frac{10^{3}}{10^{-22}} )$ = $0.25316*10^{25}$ = $2.5316*10^{24}$
a million has 9 zeroes
so 24 zeroes is alot that is a <span>septillion, so there are 2.5316 septillion uranium atoms in 1kg

a. 4
b. underestimate

</span>

5 0

3 years ago

Find the volume of the sphere .<br> (Geometry)

asambeis [7]

Answer:

V = 32/3 pi

Step-by-step explanation:

The volume of a sphere is given by

V= 4/3 pi r^3

We know the radius is 2

V = 4/3 pi (2)^3

V = 4/3 pi (8)

V = 32/3 pi

6 0

3 years ago

A Confidence interval is desired for the true average stray-load loss mu (watts) for a certain type of induction motor when the

Vaselesa [24]

Answer:

A sample size of 35 is needed.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, find the width W as such

$W = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How large must the sample size be if the width of the 95% interval for mu is to be 1.0:

We need to find n for which W = 1.

We have that $\sigma^{2} = 9$ , then $\sigma = \sqrt{\sigma^{2}} = \sqrt{9} = 3$ . So

$W = z*\frac{\sigma}{\sqrt{n}}$

$1 = 1.96*\frac{3}{\sqrt{n}}$

$\sqrt{n} = 1.96*3$

$(\sqrt{n})^2 = (1.96*3)^{2}$

$n = 34.57$

Rounding up

A sample size of 35 is needed.

3 0

3 years ago

Find the roots of the function.

Korolek [52]

The answer is -9i , 9i
x^2+81=0
x^2=-81
x=√-81
=9i,-9i

4 0

3 years ago

Read 2 more answers

What is the definition of percent of change

Sonja [21]

Ratio of amount of change to original shown as a percent.

4 0

3 years ago