Answer:
Mean: 40.17 years.
Standard deviation: 10.97 years.
Step-by-step explanation:
The frequency distribution is in the attached image.
We can calculate the mean adding the multiplication of midpoints of each class and frequency, and dividing by the sample size.
The midpoints of a class is calculated as the average of the bounds of the class.
Then, the mean can be written as:

The standard deviation can be calculated as:
![s=\sqrt{\dfrac{1}{N-1}\sum f_i(X_i-E(X))^2}\\\\\\s=\sqrt{\dfrac{1}{59}[3(15-40.17)^2+7(25-40.17)^2+18(35-40.17)^2+20(45-40.17)^2+12(55-40.17)^2]}](https://tex.z-dn.net/?f=s%3D%5Csqrt%7B%5Cdfrac%7B1%7D%7BN-1%7D%5Csum%20f_i%28X_i-E%28X%29%29%5E2%7D%5C%5C%5C%5C%5C%5Cs%3D%5Csqrt%7B%5Cdfrac%7B1%7D%7B59%7D%5B3%2815-40.17%29%5E2%2B7%2825-40.17%29%5E2%2B18%2835-40.17%29%5E2%2B20%2845-40.17%29%5E2%2B12%2855-40.17%29%5E2%5D%7D)

Answer:
A triangle and an octagon
Step-by-step explanation:
Let me know if either one of them is wrong
(2,3) I think. I'm not in Algebra 1, so yeah
I'm not sure what you mean by this, but if you mean rounding, I got an answer.
Say you're rounding 24 to 30.
24 is closer to 20 than 30.
But if you were rounding 25 to 30, 25 would be closer to 30, not 20.
I guess it's kind of confusing.
Answer:

Step-by-step explanation:
2>c/3
Multiply both sides of the inequality by 3.
2(3)>c/3(3)
6>c
Switch sides.
c<6