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3 years ago

What are the answer to these questions:

Mathematics

1 answer:

Tomtit [17]3 years ago

3 0

1. 40/60 + 15/60 + 24/60 + 10/60 = 1.48

2.30/60 + 20/60 + 15/60 + 12/60 + 10/60 = 1.45

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f) The life of a power transmission tower is exponentially distributed, with mean life 25 years. If three towers, operated indep

Step2247 [10]

Answer:

15.24% probability that at least 2 will still stand after 35 years

Step-by-step explanation:

To solve this question, we need to understand the binomial distribution and the exponential distribution.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

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:

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

Probability of a single tower being standing after 35 years:

Single tower, so exponential.

Mean of 25 years, so $m = 25, \mu = \frac{1}{25} = 0.04$

We have to find $P(X > 35)$

$P(X > 35) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-0.04*35} = 0.2466$

What is the probability that at least 2 will still stand after 35 years?

Now binomial.

Each tower has a 0.2466 probability of being standing after 35 years, so $p = 0.2466$

3 towers, so $n = 3$

We have to find:

$P(X \geq 2) = P(X = 2) + P(X = 3)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 2) = C_{3,2}.(0.2466)^{2}.(0.7534)^{1} = 0.1374$

$P(X = 3) = C_{3,3}.(0.2466)^{3}.(0.7534)^{0} = 0.0150$

$P(X \geq 2) = P(X = 2) + P(X = 3) = 0.1374 + 0.0150 = 0.1524$

15.24% probability that at least 2 will still stand after 35 years

4 0

3 years ago

What is the measure of ∠L?

otez555 [7]

<h3>Answer: 72.54</h3>

====================================================

Explanation:

We set up a cosine ratio, since we want to connect the adjacent and hypotenuse. Then we'll use the inverse cosine, which is also known as arccosine, to isolate the angle value.

This is what your steps could look like:

cos(angle) = adjacent/hypotenuse

cos(L) = LM/LN

cos(L) = 18/60

cos(L) = 0.3

L = arccos(0.3)

L = 72.542396876278 which is approximate

L = 72.54 degrees approximately

Make sure your calculator is in degree mode.

8 0

3 years ago

X^2 + 5x - 24 = 0 How do I solve by factoring

tiny-mole [99]

Answer:

x = -8 or x = 3

Step-by-step explanation:

To factor ax² + bx + c, use AC method.

a times c is 1 × -24 = -24.

Factors of ac (-24) that add up to b (5) are 8 and -3.

Divide by a and reduce: 8/1 and -3/1.

Therefore, the factors are x + 8 and x − 3.

x² + 5x − 24 = 0

(x + 8) (x − 3) = 0

x = -8 or 3

7 0

3 years ago

Do 3/7 and 7/3 represent the same length on a number line?

Anna [14]

No 3/7 do not represents the same length on the number line

5 0

4 years ago

Read 2 more answers

PLEASE HELP AS FAST AS POSSIBLE

EleoNora [17]

Answer:

Step-by-step explanation:

The order goes as follows:

Lower Extreme, Lower Quartile, Median, Higher Quartile, Higher Extreme

The Higher Extreme is the highest quantity.

I am joyous to assist you anytime.

5 0

3 years ago