(-3 1/2)-(-4 1/4)= -7/2-(-17/4) equals what

An airplane has 100 seats for passengers. Assume that the probability that a person holding a ticket appears for the flight is 0

zmey [24]

Answer:

96.33% probability that everyone who appears for the flight will get a seat

Step-by-step explanation:

I am going to use the binomial approximation to the normal to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$n = 105, p = 0.9$

So

$\mu = E(X) = np = 105*0.9 = 94.5$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{105*0.9*0.1} = 3.07$

What is the probability that everyone who appears for the flight will get a seat

100 or less people appearing to the flight, which is the pvalue of Z when X = 100. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{100 - 94.5}{3.07}$

$Z = 1.79$

$Z = 1.79$ has a pvalue of 0.9633

96.33% probability that everyone who appears for the flight will get a seat

7 0

3 years ago

Expresión for the calculation 5 times the number 25 and then subtract the quotient of 14 and 7

Rudik [331]

Answer:

(5*25) - (14/7)

<em>* means multiply and / means divide</em>

7 0

3 years ago

Determine if the function is one-to-one.<br><br>

olya-2409 [2.1K]

Answer:

No

Step-by-step explanation:

From what I saw on google for what "one to one" means, It's basically meaning that the bottom of that quadratic function is at point (0 , 0) and hits both (-1 , 1) and (1 , 1) on the graph.

4 0

3 years ago

What number is 250% of 4.2?

agasfer [191]

Answer

10.5

Step-by-step explanation:

6 0

3 years ago

Kirby is four miles from the train station, from which a train is due to leave in 56 minutes. Kirby is walking along at 3 mph, a

Luda [366]

Let's assume that Kirby walks with a speed
$v_1 = 3 mph$
for a time $t_1$ , and that he runs with a speed
$v_2 = 12 mph$
for a time $t_2$ .

The total time available for Kirby to catch the train is:
$t=56 min = 0.93 h$
and this must be equal to the sum of the two times t1 and t2:
$0.93 = t_1 + t_2$

The distance Kirby should cover is
$S=4 m$
and this should be equal to the sum of the distances covered by walking and by running:
$4 = S_1 + S_2 = v_1 t_1 + v_2 t_2 = 3 t_1 + 12 t_2$

So we have a system of 2 equations:
$0.93 = t_1 + t_2$
$4 = 3 t_1 + 12 t_2$

If we solve the system, we find:
$t_1 = 0.80 h = 48 min$
$t_2 = 0.13 h = 8 min$

So, Kirby needs to run at least for 8 minutes in order to catch the train.

6 0

3 years ago