Answer:
x =52
Step-by-step explanation:
bith angels together make 180° so 180-128=52
To finish in 5 weeks:
For 4 of those weeks, read 4 chapters per week. On one of the weeks read 3 chapters.
To finish in 4 weeks:
For 3 of those weeks, read 5 chapters per week. On one of the weeks read 4 chapters.
To finish in 3 weeks:
For 2 of those weeks, read 6 chapters per week. On one of the weeks read 7 chapters.
To finish in 2 weeks:
On one week read 10 chapters. On the other week read 9 chapters.
To finish in 7 days:
For 6 of those days, read 3 chapters. On one of the days, read 1 chapter.
Answer:
μ ≈ 2.33
σ ≈ 1.25
Step-by-step explanation:
Each person has equal probability of ⅓.
![\left[\begin{array}{cc}X&P(X)\\1&\frac{1}{3}\\2&\frac{1}{3}\\4&\frac{1}{3}\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7DX%26P%28X%29%5C%5C1%26%5Cfrac%7B1%7D%7B3%7D%5C%5C2%26%5Cfrac%7B1%7D%7B3%7D%5C%5C4%26%5Cfrac%7B1%7D%7B3%7D%5Cend%7Barray%7D%5Cright%5D)
The mean is the expected value:
μ = E(X) = ∑ X P(X)
μ = (1) (⅓) + (2) (⅓) + (4) (⅓)
μ = ⁷/₃
The standard deviation is:
σ² = ∑ (X−μ)² P(X)
σ² = (1 − ⁷/₃)² (⅓) + (2 − ⁷/₃)² (⅓) + (4 − ⁷/₃)² (⅓)
σ² = ¹⁴/₉
σ ≈ 1.25