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sashaice [31]
2 years ago
13

The length of time it takes to get through the security checks at a very large urban airport is a random variable with mean μ =

20.6 minutes and standard deviation σ = 8.4 minutes. a simple random sample of 36 airline passengers is to be observed going through security. for the passengers in the srs, what is the approximate probability that the mean length of time for them to get through security will be less than 18 minutes?
Mathematics
1 answer:
gregori [183]2 years ago
8 0
A) The population and sample mean are always the same ... in this case, it is 20.6 minutes. 

<span>b) First convert the data to z-values: </span>

<span>P(X<18) = P(z < (18-20.6)/8.4) = P(z< -0.3095) </span>

<span>Now, using a Standard Normal table, look up z= -0.3095 </span>

<span>P(X<18) = 0.3785 </span>

<span>Hope that helps</span>
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Devon and his friends bought strawberry wafers for $3 per packet and chocolate wafers for $1 per packet at a carnival. They spen
Irina-Kira [14]
Hi there!

PART A:
The system of equations we would use would be:
x + y = 22 (amount of items)
3x + 1y = 30 (cost)

Variables:
x = the amount of strawberry wafers bought at the price of $3
y = the amount of chocolate wafers bought at the price of $1

PART B:
To solve, we'll use substitution because we can easily isolate a variable using the first equation.

Work:
x + y = 22 (first equation)
y = 22 - x (isolating a variable)
3x + 1y = 30 (second equation)
3x + (22 - x) = 30 (substituting into the second equation)
2x + 22 = 30 (simplifying)
2x = 8 (subtracting)
x = 4 strawberry wafers
4 + y = 22 (substituting x into the first equation to solve for y)
y = 18 chocolate wafers

ANSWER:
They bought 4 strawberry wafers and 18 chocolate wafers.

Hope this helps!! :)
If there's anything else that I can help you with, please let me know!
8 0
2 years ago
Suppose we want to choose 5 objects, without replacement, from 13 distinct objects. (a) How many ways can this be done, if the o
Arisa [49]

Answer:

A. 1, 287 ways

B. 154,440 ways

Step-by-step explanation:

A. We want to choose 5 objects from a total 13, without considering the order in which they are chosen.

The correct way to do this is by using the combination formula since order is not considered;

Thus we have ; 13 C 5 read as 13 combination 5;

Mathematically, n C r is ; n!/(n-r)!r!

Thus, we have ;

13!/(13-8)!8! = 13!/5!8! = 1,287 ways

B. By considering order, we shall be using the permutation formula;

Mathematically n P r = n!/(n-r)!

Read as n permutation r;

Using the numbers involved, we have ; 13 P 5

= 13!/(13-5)! = 13!/8! = 154,440 ways

8 0
2 years ago
Simplify these expressions.<br> a. 4x + 7x + (–x)<br> b. –5yz + yz + 2yz
salantis [7]

Answer:A. 10x. B. -2yz

Step-by-step explanation:

A. 4x+7x=11x

11x+(-x) = 11x-1x=10x

B. -5yz+yz=-4yz

-4yz+2yz=-2yz

4 0
2 years ago
Stan's cookie recipe makes 242424 cookies and calls for exactly 384384384 sprinkles. He is wondering how many sprinkles (p)(p)le
arlik [135]
If these numbers are correct:

For every 242,424 cookies he needs 384,384,384 sprinkles. So how many sprinkles does he need for 606,060 cookies?

242,424/384,384,384 = 606,060/x

384,384,384 * 606,060 = 242,424 * x

232,959,999,767,040 = 242,424 * x

960,960,960 = x
7 0
2 years ago
The tax rate as a percent, r, charged on an item can be determined using the formula StartFraction c Over p EndFraction minus 1
Nataliya [291]

Answer:

43.20

Step-by-step explanation:

Had to take one for the team

4 0
1 year ago
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