Answer:
b. 239
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find M as such
In which is the standard deviation of the population and n is the size of the sample.
In this problem, we have that:
So a sample of at least 239 is required.
The correct answer is:
b. 239
Answer:
Let's let g = Dr. Garcia's age and s = his son's age.
g = 2s, right?
20 years ago, Dr. Garcia was g - 20 years old. He was also 4(s - 20), 4 times his son's age 7 years ago.
g - 20 = 4(s - 20)
g - 20 = 4s - 80
In the first equation, we have g = 2s. We are going to substitute this g into the second equation.
2s - 20 = 4s - 80
60 = 2s
s = 30
So, his son is 30 and Mr. Garcia is 60. 30 x 2 = 60.
20 years ago, his son would have been 10 and Mr. Garcia would have been 40. 10 x 4 = 40.
Step-by-step explanation:
Brainliest?
C because 8- -1 = 9 and when flipped the end is -1 and the end non flipped is 8
Answer:
9
Step-by-step explanation:
cos39= 7/x
x = 7/cos39
x= 9
Answer:
His average rate of speed for the entire trip is 10 miles/hour.
Step-by-step explanation:
We are given that John went on a bike ride to the store 4 miles away. If it took John 3/10 of an hour to get there and 1/2 of an hour to get back.
And we have to find his average rate of speed (miles per hour) for the entire trip.
As we know that the Distance-Speed-Time formula is given by;
Here, the distance for the entire trip = 8 miles (4 miles for reaching store and 4 miles for returning back)
The time taken for the entire trip = of an hour to reach the store and an hour to get back.
So, the average rate of speed for the entire trip =
=
= = 10 miles per hour
Hence, his average rate of speed for the entire trip is 10 miles/hour.