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1 year ago

What is the value of the expression when n = 3? - 2n(5 + n-8-3n)

Mathematics

1 answer:

lys-0071 [83]1 year ago

5 0

Answer:

54

Step-by-step explanation:

- 2n(5 + n - 8 - 3n) =

replace n = 3

- 2(3)(5 + 3 - 8 - 3×3)

= - 6(8 - 8 - 9)

= - 6(0 - 9)

= - 6 × - 9

= 54

(-)(-) = +

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The prices of three t-shirts styles are $24, $30 and $36. the probability of choosing a $24 t-shirt is 1/6. the probability of c

Slav-nsk [51]

$\text{Answer} : \text{The expected value of a t-shirt is \$31.}$

Explanation:

Since we have given that

The prices of three t-shirts styles i.e $24, $30, $36 with their probability is given by

$\frac{1}{6}, \frac{1}{2},\frac{1}{3}$

As we know that,

$E(X)= \sum_{1}^{3}x_iP(x_i)$

$\text{where} x_i \text{ is the prices of t- shirts styles}$

Now,

$x_1= \$24 , x_2=\$30 , x_3=$36$

and

$P(x_1)=\frac{1}{6},P(x_2)=\frac{1}{2}, P(x_3)=\frac{1}{3}$

So,

$E(X)= 24\times \frac{1}{6}+30\times\frac{1}{2}+36\times \frac{1}{3}\\=4+15+12\\=31$

So, the expected value of a t-shirt = $31.

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2 years ago

Circle D is shown. Angle A C B intercepts arc A B. Arc A B has a measure of 76 degrees. What is the measure of AngleC ? 38° 76°

Valentin [98]

I think the answer is 76 ...

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2 years ago

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HEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEELLLLLLLLLLLLLLLLLLLLLLLLP What is the simplified value of the expression below?

olganol [36]

Answer:

100

Step-by-step explanation:

start with what's in the parenthesis':

8 (9.75 - 3.25) + 12 x 4 = 8 (6.50) + 12 x 4

then take the number outside of the parenthesis' time the number inside of them:

8 (6.50) + 12 x 4 = 52 + 12 x 4

now, take the product of the two number on the right side of the addition sign:

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finally, add the final two numbers together:

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1 year ago

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Bill buys and sells laptops. Last month Bill bought 50 laptops. He paid £400 for each laptop. He sold 40 of these laptops at a p

Ivenika [448]

Answer:

As Bill's sales is £25400, which is greater than £25000, he achieved his target.

Step-by-step explanation:

Cost of each laptop = £400

lets calculate for 40 laptops first

Given, he sold 40 of these at 30% profit

30% of cost price = 30% of £400 = 30/100 * 400 = 120

Therefore, selling price of these laptops = £400 + £120 = £520

Total sales generated from selling 40 of these laptop = 40*£520

= £520 =£20,800

lets calculate for 10 laptops now

Given, he sold 10 of these at 15% profit

15% of cost price = 15% of £400 = 15/100 * 400 = 60

Therefore, selling price of these laptops = £400 + £60 = £460

Total sales generated from selling 10 of these laptop = 10*£460

= £4600

Total sales generated from selling all the 50 laptop =

Total sales generated from selling 40 of these laptop + Total, sales generated from selling 10 of these laptop = £20,800 + £4600 = £25,400

Target for Bill = £25000

As his sales is £25400, which is greater than £25000, he achieved his target.

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2 years ago

The average lifetime of a certain new cell phone is 3.4 years. The manufacturer will replace any cell phone failing within three

melisa1 [442]

Answer:

68% of these phones last 3.87 years.

Step-by-step explanation:

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

$f(x) = \mu e^{-\mu x}$

In which $\mu = \frac{1}{m}$ is the decay parameter.

The probability that x is lower or equal to a is given by:

$P(X \leq x) = \int\limits^a_0 {f(x)} \, dx$

Which has the following solution:

$P(X \leq x) = 1 - e^{-\mu x}$

The probability of finding a value higher than x is:

$P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}$

The average lifetime of a certain new cell phone is 3.4 years.

This means that $m = 3.4, \mu = \frac{1}{3.4} = 0.2941$

$P(X \leq x) = 1 - e^{-0.2941x}$

68% of these phones last how long (in years)?

This is x for which:

$P(X \leq x) = 0.68$

$P(X \leq x) = 1 - e^{-0.2941x}$

Then

$0.68 = 1 - e^{-0.2941x}$

$e{-0.2941x} = 0.32$

$\ln{e{-0.2941x}} = \ln{0.32}$

$-0.2941x = \ln{0.32}$

$x = -\frac{\ln{0.32}}{0.2941}$

$x = 3.87$

68% of these phones last 3.87 years.

4 0

1 year ago