Answer:
a) (1215, 1297)
b) (1174, 1338)
c) (1133, 1379)
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 1256
Standard Deviation, σ = 41
Empirical Rule:
- Also known as 68-95-99.7 rule.
- It states that almost all the data lies within three standard deviation for a normal data.
- About 68% of data lies within 1 standard deviation of mean.
- About 95% of data lies within two standard deviation of mean.
- About 99.7% of data lies within 3 standard deviation of mean.
a) range of years centered about the mean in which about 68% of the data lies

68% of data will be found between 1215 years and 1297 years.
b) range of years centered about the mean in which about 95% of the data lies

95% of data will be found between 1174 years and 1338 years.
c) range of years centered about the mean in which about all of the data lies

All of data will be found between 1133 years and 1379 years.
Answer:
I've attached the Answer
Step-by-step explanation:
here it is
so, this is a quadratic equation, meaning two solutions, and we have a factored form of it, meaning you can get the solutions by simply zeroing out the f(x).
![\bf \stackrel{f(x)}{0}=-(x-3)(x+11)\implies 0=(x-3)(x+11)\implies x= \begin{cases} 3\\ -11 \end{cases} \\\\\\ \boxed{-11}\stackrel{\textit{\large 7 units}}{\rule[0.35em]{10em}{0.25pt}}-4\stackrel{\textit{\large 7 units}}{\rule[0.35em]{10em}{0.25pt}}\boxed{3}](https://tex.z-dn.net/?f=%5Cbf%20%5Cstackrel%7Bf%28x%29%7D%7B0%7D%3D-%28x-3%29%28x%2B11%29%5Cimplies%200%3D%28x-3%29%28x%2B11%29%5Cimplies%20x%3D%20%5Cbegin%7Bcases%7D%203%5C%5C%20-11%20%5Cend%7Bcases%7D%20%5C%5C%5C%5C%5C%5C%20%5Cboxed%7B-11%7D%5Cstackrel%7B%5Ctextit%7B%5Clarge%207%20units%7D%7D%7B%5Crule%5B0.35em%5D%7B10em%7D%7B0.25pt%7D%7D-4%5Cstackrel%7B%5Ctextit%7B%5Clarge%207%20units%7D%7D%7B%5Crule%5B0.35em%5D%7B10em%7D%7B0.25pt%7D%7D%5Cboxed%7B3%7D)
so the zeros/solutions are at x = 3 and x = -11, now, bearing in mind the vertex will be half-way between those two, checking the number line, that midpoint will be at x = -4, so the vertex is right there, well, what's f(x) when x = -4?
![\bf f(-4)=-(-4-3)(-4+11)\implies f(-4)=7(7)\implies f(-4)=49 \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{vertex}{(-4~~,~~49)}~\hfill](https://tex.z-dn.net/?f=%5Cbf%20f%28-4%29%3D-%28-4-3%29%28-4%2B11%29%5Cimplies%20f%28-4%29%3D7%287%29%5Cimplies%20f%28-4%29%3D49%20%5C%5C%5C%5C%5B-0.35em%5D%20%5Crule%7B34em%7D%7B0.25pt%7D%5C%5C%5C%5C%20~%5Chfill%20%5Cstackrel%7Bvertex%7D%7B%28-4~~%2C~~49%29%7D~%5Chfill)
Answer: 26 years.
Step-by-step explanation:
Let x = current age of Louise (in years).
Then current age of James = x+6
Eight years from now, James's age = x+6+8= x+14
4 years ago, Louise's age = x-4
According to the question
x+14 = 4(x-4)
⇒ x+14 = 4x-16
⇒ 4x-x = 16+14
⇒ 3x = 30
⇒ x= 10 = current age of Louise (in years).
current age of James = 10+6 = 16 years
Sum of current ages = 16+10=26 years.
hence, the sum of the current ages is 26 years.