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ira [324]
3 years ago
12

Find the missing number ___:7 = 12:21a.14b.12c.4d.3

Mathematics
1 answer:
Novay_Z [31]3 years ago
6 0
x:7=12:21\to\dfrac{x}{7}=\dfrac{12}{21}\ \ \ |cross\ multiply\\\\21x=7\cdot12\\21x=84\ \ \ |divide\ both\ sides\ by\ 21\\\boxed{x=4}\\\\Other\ method:\\\dfrac{x}{7}=\dfrac{12}{21}\\\\21:7=\boxed3\to12:\boxed3=4\\\\\boxed{\frac{4}{7}=\frac{12}{21}\to4:7=12:21}
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A grocery store’s receipts show that Sunday customer purchases have a skewed distribution with a mean of 27$ and a standard devi
34kurt

Answer:

(a) The probability that the store’s revenues were at least $9,000 is 0.0233.

(b) The revenue of the store on the worst 1% of such days is $7,631.57.

Step-by-step explanation:

According to the Central Limit Theorem if we have a population with mean μ and standard deviation σ and we take appropriately huge random samples (n ≥ 30) from the population with replacement, then the distribution of the sum of values of X, i.e ∑X, will be approximately normally distributed.  

Then, the mean of the distribution of the sum of values of X is given by,  

 \mu_{X}=n\mu

And the standard deviation of the distribution of the sum of values of X is given by,  

\sigma_{X}=\sqrt{n}\sigma

It is provided that:

\mu=\$27\\\sigma=\$18\\n=310

As the sample size is quite large, i.e. <em>n</em> = 310 > 30, the central limit theorem can be applied to approximate the sampling distribution of the store’s revenues for Sundays by a normal distribution.

(a)

Compute the probability that the store’s revenues were at least $9,000 as follows:

P(S\geq 9000)=P(\frac{S-\mu_{X}}{\sigma_{X}}\geq \frac{9000-(27\times310)}{\sqrt{310}\times 18})\\\\=P(Z\geq 1.99)\\\\=1-P(Z

Thus, the probability that the store’s revenues were at least $9,000 is 0.0233.

(b)

Let <em>s</em> denote the revenue of the store on the worst 1% of such days.

Then, P (S < s) = 0.01.

The corresponding <em>z-</em>value is, -2.33.

Compute the value of <em>s</em> as follows:

z=\frac{s-\mu_{X}}{\sigma_{X}}\\\\-2.33=\frac{s-8370}{316.923}\\\\s=8370-(2.33\times 316.923)\\\\s=7631.56941\\\\s\approx \$7,631.57

Thus, the revenue of the store on the worst 1% of such days is $7,631.57.

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2 years ago
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Marina CMI [18]

Answer:

95.5

Step-by-step explanation:

you can using toa

tan = opp/adj

tan 37° = 72/x

x = 72/ tan 37°

x = 95.547 feet

x = 95.5

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3 years ago
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vova2212 [387]
The temperature decreased by 5 degrees per hour, as -25 / 5 is -5.
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Answer:

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