Flora made 7 withdrawals of 275

A train travels 200 miles in 4 hours at a constant rate. What is the constant rate of change for the train in miles per hour? A.

Sav [38]

Answer:50 miles

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

United Airlines' flights from Denver to Seattle are on time 50 % of the time. Suppose 9 flights are randomly selected, and the n

Ivanshal [37]

Answer:

a) The probability that exactly 4 flights are on time is equal to 0.0313

b) The probability that at most 3 flights are on time is equal to 0.0293

c) The probability that at least 8 flights are on time is equal to 0.00586

Step-by-step explanation:

The question posted is incomplete. This is the complete question:

United Airlines' flights from Denver to Seattle are on time 50 % of the time. Suppose 9 flights are randomly selected, and the number on-time flights is recorded. Round answers to 3 significant figures.

a) The probability that exactly 4 flights are on time is =

b) The probability that at most 3 flights are on time is =

c)The probability that at least 8 flights are on time is =

<h2>Solution to the problem</h2>

a) Probability that exactly 4 flights are on time

Since there are two possible outcomes, being on time or not being on time, whose probabilities do not change, this is a binomial experiment.

The probability of success (being on time) is p = 0.5.

The probability of fail (note being on time) is q = 1 -p = 1 - 0.5 = 0.5.

You need to find the probability of exactly 4 success on 9 trials: X = 4, n = 9.

The general equation to find the probability of x success in n trials is:

$P(X=x)=_nC_x\cdot p^x\cdot (1-p)^{(n-x)}$

Where $_nC_x$ is the number of different combinations of x success in n trials.

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

Hence,

$P(X=4)=_9C_4\cdot (0.5)^4\cdot (0.5)^{5}$

$_9C_4=\frac{4!}{9!(9-4)!}=126$

$P(X=4)=126\cdot (0.5)^4\cdot (0.5)^{5}=0.03125$

b) Probability that at most 3 flights are on time

The probability that at most 3 flights are on time is equal to the probabiity that exactly 0 or exactly 1 or exactly 2 or exactly 3 are on time:

$P(X\leq 3)=P(X=0)+P(X=1)+P(X=2)+P(X=3)$

$P(X=0)=(0.5)^9=0.00195313$ . . . (the probability that all are not on time)

$P(X=1)=_9C_1(0.5)^1(0.5)^8=9(0.5)^1(0.5)^8=0.00390625$

$P(X=2)=_9C_2(0.5)^2(0.5)^7=36(0.5)^2(0.5)^7=0.0078125$

$P(X=3)= _9C_3(0.5)^3(0.5)^6=84(0.5)^3(0.5)^6=0.015625$

$P(X\leq 3)=0.00195313+0.00390625+0.0078125+0.015625=0.02929688\\\\ P(X\leq 3) \approx 0.0293$

c) Probability that at least 8 flights are on time 

That at least 8 flights are on time is the same that at most 1 is not on time.

That is, 1 or 0 flights are not on time.

Then, it is easier to change the successful event to not being on time, so I will change the name of the variable to Y.

$P(Y=0)=_0C_9(0.5)^0(0.5)^9=0.00195313\\ \\ P(Y=1)=_1C_9(0.5)^1(0.5)^8=0.0039065\\ \\ P(Y=0)+P(Y=1)=0.00585938\approx 0.00586$

6 0

3 years ago

Find 5% of $43.79. $218.95 $2.19 $21.90 $2,189.50

ddd [48]

43.79 *0.05= 2.1895
218.95 *0.05= 10.9475
2.19 *0.05= 0.1095
21.90 *0.05= 1.095
2,189.50 *0.05= 109.475

hope this helps

8 0

3 years ago

If z=2.5, x=102 and x=100, what is s?

Bad White [126]

I believe the problem ask for s which is the standard deviation. We must recall that the formula for z statistic is stated as:

z = (x – x over bar) / s

Where,

z = z statistic = 2.5

x = sample value or sample score = 102

x over bar = the sample mean or sample average = 100

s = standard deviation = unknown

Rewriting the equation in terms of s:

s = (x – x over bar) / z

Substituting the given values into the equation:

s = (102 – 100) / 2.5

s = 0.8

Therefore the standard deviation s is 0.8

7 0

2 years ago

what does this mean when a rhombus is split into 2 triangles ; what's the formula to find the value of x? also it's about polygo

tangare [24]

Answer/Step-by-step explanation:

The rhombus when split into two triangles will give us two equilateral triangles that are congruent to each other.

Therefore:

The two bases of both triangles will have equal angle measures of 4x + 5 each and a third angle measure of 8x - 6.

✅Formula to find the value of x:

(8x - 6) + 2(4x + 5) = 180° (sum of triangle)

8x - 6 + 8x + 10 = 180

8x + 8x - 6 + 10 = 180

16x + 4 = 180

16x + 4 - 4 = 180 - 4

16x = 176

16x/16 = 176/16

x = 11

3 0

2 years ago