Answer:
a. 0.8366
b. No
Step-by-step explanation:
We will use the central limit theorem which can be applied to a random sample from any distribution as long as the mean and the variance are both finite and the sample size is large (the sample size n should be greater than 30). Here we have that the tip percentage at the restaurant has a mean value of 18% and a standard deviation of 6%, then because of the central limit theorem, we know that the sample mean tip percentage is approximately normally distributed with mean 18% and standard deviation 
.
a. The z-score related to 16% is given by (16-18)/0.9487 = -2.1081 and the z-score related to 19% is given by (19-18)/0.9487 = 1.0541. We are looking for 
b. If the sample size had been 15 rather than 40, then, the probability requested in part (a) could not be calculated from the given information, this because the central limit theorem only applies when the sample size is large, for example n > 30.
Answer:
3 1/3 miles The answer is D
Step-by-step explanation:
The first trip to school is 5/6 miles. Multiply that by 2 because she also walked home and you get 10/6. Then add the distance she she walked to the library- which simplifies to 5/6 and you get 20/6. That simplifies to 3 1/3.
Write the equation of the first train: x = 12t
Write the equation of the second train: y = -20t+72, assuming the train one is at the origins when t = 0.
Now solve the equation: 12t=-20t+72,
32t = 72, then t = 2.25 hours. The two train meet after 2.25 hours.
Now the equation of the <span>pigeon is like this: x = 48t.
</span>Then for t = 2.25, we get
<span>
The Hyde has flown 108 km when the trains meet.</span>
Answer:
x ∈ (-∞, -1) ∪ (1, ∞)
Step-by-step explanation:
To solve this problem we must factor the expression that is shown in the denominator of the inequality.
So, we have:
So the roots are:
Therefore we can write the expression in the following way:
Now the expression is as follows:
Now we use the study of signs to solve this inequality.
We have 3 roots for the polynomials that make up the expression:
We know that the first two are not allowed because they make the denominator zero.
Observe the attached image.
Note that:
when 
when 
and
is always 
Finally after the study of signs we can reach the conclusion that:
x ∈ (-∞, -1) ∪ (1, 2] ∪ [2, ∞)
This is the same as
x ∈ (-∞, -1) ∪ (1, ∞)
Answer:
2
Step-by-step explanation:
5/8 8 people in all, 5 were in spin class, 1 was lifting weights, 2 were running.
