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kirza4 [7]

The value of X = 10. A is the answer. You will equate the denominator by multiplying by the numerator and eventually you will get you answer which is 10

8 0

3 years ago

The life of a red bulb used in a traffic signal can be modeled using an exponential distribution with an average life of 24 mont

BartSMP [9]

Answer:

See steps below

Step-by-step explanation:

Let X be the random variable that measures the lifespan of a bulb.

If the random variable X is exponentially distributed and X has an average value of 24 month, then its probability density function is

$\bf f(x)=\frac{1}{24}e^{-x/24}\;(x\geq 0)$

and its cumulative distribution function (CDF) is

$\bf P(X\leq t)=\int_{0}^{t} f(x)dx=1-e^{-t/24}$

• What is probability that the red bulb will need to be replaced at the first inspection?

The probability that the bulb fails the first year is

$\bf P(X\leq 12)=1-e^{-12/24}=1-e^{-0.5}=0.39347$

• If the bulb is in good condition at the end of 18 months, what is the probability that the bulb will be in good condition at the end of 24 months?

Let A and B be the events,

A = “The bulb will last at least 24 months”

B = “The bulb will last at least 18 months”

We want to find P(A | B).

By definition P(A | B) = P(A∩B)P(B)

but B⊂A, so A∩B = B and

$\bf P(A | B) = P(B)P(B) = (P(B))^2$

We have

$\bf P(B)=P(X>18)=1-P(X\leq 18)=1-(1-e^{-18/24})=e^{-3/4}=0.47237$

hence,

$\bf P(A | B)=(P(B))^2=(0.47237)^2=0.22313$

• If the signal has six red bulbs, what is the probability that at least one of them needs replacement at the first inspection? Assume distribution of lifetime of each bulb is independent

If the distribution of lifetime of each bulb is independent, then we have here a binomial distribution of six trials with probability of “success” (one bulb needs replacement at the first inspection) p = 0.39347

Now the probability that exactly k bulbs need replacement is

$\bf \binom{6}{k}(0.39347)^k(1-0.39347)^{6-k}$

<em>Probability that at least one of them needs replacement at the first inspection = 1- probability that none of them needs replacement at the first inspection. </em>

This means that,

<em>Probability that at least one of them needs replacement at the first inspection = </em>

$\bf 1-\binom{6}{0}(0.39347)^0(1-0.39347)^{6}=1-(0.60653)^6=0.95021$

5 0

3 years ago

Timothy made 60 quarts of cider he poured the cider into containers. Each container holds 4/11 of a quart. How many containers d

Dahasolnce [82]

60 / (4/11) =
60 * 11/4 =
660/4 =
165 containers

7 0

3 years ago

Read 2 more answers

A radio station requires DJs to play 3 commercials for every 18 songs they play. What is the unit rate of songs to commercials?

bulgar [2K]

6 songs

The way to find this answer is to divide 18 by 3, which is six, which means that after every six songs a commercial is played.

Hope this was helpful and that I explained it correctly.

3 0

3 years ago

A ___ is a transformation that changes the size but not the shape of a figure. A dilation can ____ or ____ a figure

Liula [17]

Answer:

1) Dilation

2) enlarge or shrink

Step-by-step explanation:

1) The shape stays the same, but the area and size change based upon the scale factor (k)

2) Dilation can shrink or enlarge something based upon a scale factor

Vote Brainliest!!

8 0

3 years ago