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3 years ago

27 solid iron spheres, each of radius 'xcm'ate melted to form a sphere with radius 'ycm',find the ratio x:y

Mathematics

1 answer:

r-ruslan [8.4K]3 years ago

7 0

Answer:3:1

Step-by-step explanation:

Given

There are 27 solid spheres of radius x cm

The volume of a sphere is $\frac{4}{3}\pi r^3$

The volume of 27 old spheres is the same as the volume of a new sphere

The volume of the old spheres is

$V_o=\dfrac{4}{3}\pi x^3$

The volume of a new sphere is

$V_n=\dfrac{4}{3}\pi y^3$

Now, $V_o=V_n$

$\Rightarrow 27\times \dfrac{4}{3}\pi x^3=\dfrac{4}{3}\pi y^3\\\\\Rightarrow (\dfrac{x}{y})^3=27\\\\\Rightarrow \dfrac{x}{y}=3$

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Reuben bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $150 more than the desktop. He p

cupoosta [38]

Same case as Pablo's, more or less.

a = price for the desktop

b = price for the laptop

we know the laptop is 150 bucks more than the desktop, b = a + 150.

how much is 7% of a? (7/100) * a, 0.07a.

how much is 9.5% of b? (9.5/100) * b, 0.095b.

total interests for the financing add up to 303, 0.07a + 0.095b = 303.

$\bf \begin{cases}
\boxed{b}=a+150\\
0.07a+0.095b=303\\
----------\\
0.07a+0.095\left(\boxed{a+150} \right)=303
\end{cases}
\\\\\\
0.07a+0.095a+14.25=303\implies 0.165a=288.75
\\\\\\
a=\cfrac{288.75}{0.165}\implies a=1750$

how much was it for the laptop? well b = a + 150.

8 0

3 years ago

The rates of on-time flights for commercial jets are continuously tracked by the U.S. Department of Transportation. Recently, So

tatyana61 [14]

Answer:

The probability that at least 13 flights arrive late is 2.5196 $\times 10^{-6}$ .

Step-by-step explanation:

We are given that Southwest Air had the best rate with 80 % of its flights arriving on time.

A test is conducted by randomly selecting 18 Southwest flights and observing whether they arrive on time.

The above situation can be represented through binomial distribution;

$P(X = x) = \binom{n}{r}\times p^{r} \times (1-p)^{n-r} ; x = 0,1,2,3,.........$

where, n = number of trials (samples) taken = 18 Southwest flights

r = number of success = at least 13 flights arrive late

p = probability of success which in our question is probability that

flights arrive late, i.e. p = 1 - 0.80 = 20%

Let X = Number of flights that arrive late.

So, X ~ Binom(n = 18, p = 0.20)

Now, the probability that at least 13 flights arrive late is given by = P(X $\geq$ 13)

P(X $\geq$ 13) = P(X = 13) + P(X = 14) + P(X = 15) + P(X = 16) + P(X = 17) + P(X = 18)

= $\binom{18}{13}\times 0.20^{13} \times (1-0.20)^{18-13}+ \binom{18}{14}\times 0.20^{14} \times (1-0.20)^{18-14}+ \binom{18}{15}\times 0.20^{15} \times (1-0.20)^{18-15}+ \binom{18}{16}\times 0.20^{16} \times (1-0.20)^{18-16}+ \binom{18}{17}\times 0.20^{17} \times (1-0.20)^{18-17}+ \binom{18}{18}\times 0.20^{18} \times (1-0.20)^{18-18}$

= $\binom{18}{13}\times 0.20^{13} \times 0.80^{5}+ \binom{18}{14}\times 0.20^{14} \times 0.80^{4}+ \binom{18}{15}\times 0.20^{15} \times 0.80^{3}+ \binom{18}{16}\times 0.20^{16} \times 0.80^{2}+ \binom{18}{17}\times 0.20^{17} \times 0.80^{1}+ \binom{18}{18}\times 0.20^{18} \times 0.80^{0}$

= 2.5196 $\times 10^{-6}$ .

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3 years ago

125 divided by 100 I have to make corrections

STatiana [176]

Answer:

1.25

Step-by-step explanation:

125/100 = 1.25

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2 years ago

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saul85 [17]

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3 years ago

Kyle is creating a frame for a model car. He begins by piecing two rods together, as shown in the diagram. Justify why AM = 6. D

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Answer:

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Step-by-step explanation:

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27 solid iron spheres, each of radius 'xcm'ate melted to form a sphere with radius 'ycm',find the ratio x:y​

27 solid iron spheres, each of radius 'xcm'ate melted to form a sphere with radius 'ycm',find the ratio x:y