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2 years ago

How do I solve this?

Mathematics

1 answer:

Nat2105 [25]2 years ago

3 0

You can solve with the formula for cuadratic equations:
x=−b±√b2−4ac
2a

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Help me please

GrogVix [38]

Answer:

What is the question?

Step-by-step explanation:

3 0

3 years ago

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

Isosceles triangle ABC contains angle bisectors segment BF, segment AD, and segment CE that intersect at X.

frosja888 [35]

Answer:

D) 134°

Step-by-step explanation:

i took the test

7 0

3 years ago

Read 2 more answers

Find the value of a/b when a = 2/3 and b= 7/9

Usimov [2.4K]

Answer:

6/7

Step-by-step explanation:

2/3X9/7

simplify 9 by 3

which equals:

2/1X3/7

=6/7

7 0

3 years ago

A family purchased basketball tickets online. The total cost, c, in dollars, of t tickets can be found using the function below.

Reptile [31]

Solution:
C=32.50t+8.50
236=32.50t+8.50
236-8.50=32.50t
227.50=32.50t
227.50/32.50=32.50t/32.50
t=7

The family bought 7 tickets.

3 0

3 years ago