2x^2 - 4 = 68
add 4 to both sides
2x^2 = 72
divide both sides by 2
x^2 = 36
find the square root of each sides
x = 6, -6
ANSWER: the positive value of x is 6
Answer:
7/10 or 70%
Step-by-step explanation:
Add the number of each color of balls together to get the total
5 + 2 + 3 = 10
Add the number of all the balls that aren't black
5 + 2 = 7
Then divide how many balls that aren't black by the total. This gives us the probability the ball you choose is not black
7/10 = 0.7 or 70%
Answer:
8% of of the Us states have the names that start with W.
Step-by-step explanation:
We are told that, of the 50 states, 4 have names that start with letter W, and to figure out what percentage of U.S. states have names that start with the letter W, we need to know what what 4 is what percent of 50.
We figure this out the following way:
Percent = 
Percent = 8%
Complete question:
Assume that different groups of couples use a particular method of gender selection and each couple gives birth to one baby this mention is designed to increase the likelihood that each baby will be a girl, but assume that the method has no effect so the probability of a girl is 0.5. Assume that the group consists of 36 couples.
A) Find the mean and standard deviation for the number of girls in groups of 36 births.
B) Use the range rule of thumb to find the values separating results that are significantly low and significantly high.
C) Is the result of 33 girls significantly high? A result of 33 girls would suggest the method is effective or is not effective?
Answer:
a) mean = 18
Standard deviation =3
b) low range = 12
High range = 24
c) The result of 33 girls is significantly high. Yes, the method is effective.
Step-by-step explanation:
Given:
p = 0.5
n = 36
a) The mean is the product of n and p
Mean u = np
u = 36 * 0.5 = 18
The standard deviation is the square root of the product of n and p&q.
S.d ó = 


b) To find the range rule of thumb:
• For low range
Low range = u - 2ó
= 18 - (2 * 3)
= 12
• High range
= u + 2ó
= 18 + (2*3)
= 24
c) The result is significantly high, because 33 is greater than 24 girls.
A result of 33 girls would prove the method as effective.