I would choose D for that question
Answer:
99.7%
Step-by-step explanation:
The empirical rule formula states that:
68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ .
95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ .
99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ
Step 1
We have to find the number of standard deviations from the mean
μ = Mean = 1800 hours
σ = Standard deviation = 25 hours
For 1725 hours
μ - xσ =
1800 - 25x = 1725
25x = 1800 - 1725
25x = 75
x = 75/25
x = 3
For 1875 hours
1800 + 25x = 1875
25x = 1875 - 180
25x = 75
x = 75/25
x = 3
Step 2
From the above calculation, the bum of standard deviations from the mean is 3
Hence, the percentage of light bulbs last between 1725 hours and 1875 hours is 99.7%
The value of x in the triangle with angles 80, 40 and (13x - 5) degrees is 5.
<h3>Sum of angle in a triangle</h3>
The sum of angle in a triangle is equals to 180 degrees. Recall a triangle have three sides. Therefore,
80 + 40 + 13x - 5 = 180
120 - 5 + 13x = 180
115 + 13x = 180
subtract 115 from both sides of the equation
115 - 115 + 13x = 180 - 115
13x = 65
divide both sides by 13
13x / 13 = 65 / 13
x = 5
learn more on triangle here: brainly.com/question/15268683
..... the answer is m>-49
Answer: 7
Step-by-step explanation: First you subtract 5 from both sides to single out the -3x. Then you will have -3x = -21. You will then divide both sides by negative three because you want to single out the x. After that, you will have the answer of x = 7
