Answer:
3
Step-by-step explanation:
4(1/2+3/4)+(-2) Distribute.
2+3+(-2) Simplify.
2+3-2
5-2
3
Hope this helps!! Have an amazing day (｡･∀･)ﾉﾞ
6p+p+2-3=8p-8
7p-1=8p-8
1=1p-8
7=1p
p=7
Which expression is equivalent to -1.3 - (-1.9)−1.3−(−1.9)minus, 1, point, 3, minus, left parenthesis, minus, 1, point, 9, right
RideAnS [48]
Answer:
Choise B: 
Step-by-step explanation:
For this exercise you must remember the multiplication of signs:
By definition, equivalent expression have the same value.
Then, you can find an equivalent expression to the expression provided in the exercise by simplifying it.
So, given:
To simplify it, you can distribute the negative that is located outside of the parentheses (in order to eliminate the parentheses).
Applying this procedure, you get the following equivalent expression:
Therefore, as you can notice, the expression obtained matches with the one shown in Choice B.
The question is incomplete! Complete question along with answer and step by step explanation is provided below.
Question:
The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with σ = 30 hours. A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038 hours.
If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence, how many randomly selected 60-watt light bulbs should be tested to achieve this result?
Given Information:
standard deviation = σ = 30 hours
confidence level = 99%
Margin of error = 6 hours
Required Information:
sample size = n = ?
Answer:
sample size = n ≈ 165
Step-by-step explanation:
We know that margin of error is given by
Margin of error = z*(σ/√n)
Where z is the corresponding confidence level score, σ is the standard deviation and n is the sample size
√n = z*σ/Margin of error
squaring both sides
n = (z*σ/Margin of error)²
For 99% confidence level the z-score is 2.576
n = (2.576*30/6)²
n = 164.73
since number of bulbs cannot be in fraction so rounding off yields
n ≈ 165
Therefore, a sample size of 165 bulbs is needed to ensure a margin of error not greater than 6 hours.
Answer:
i believe it would be the last option.
Step-by-step explanation:
