Answer:
Expected number of hours before the the group exits the building = E[Number of hours] = 3.2 hours
Step-by-step explanation:
Expected value, E(X) is given as
E(X) = Σ xᵢpᵢ
xᵢ = each variable
pᵢ = probability of each variable
Let X represent the number of hours before exiting the building taking each door. Note that D = Door
D | X | P(X)
1 | 3.0 | 0.2
2 | 3.5 | 0.1
3 | 5.0 | 0.2
4 | 2.5 | 0.5
E(X) = (3×0.2) + (3.5×0.1) + (5×0.2) + (2.5×0.5) = 3.2 hours
Hope this Helps!!!

Use the formula above to find the surface area of a cylinder.
For the given cylinder the given data is the height (6mi) and diameter (16mi), use the diameter to find the radius:

Surface area:

Then, the surface area of the given cylinder is: 224π square miles
Answer:

Step-by-step explanation:
We can use formula (a-b)² = a² -2ab + b².
In our example a = 3c^4 and b = 5c^6
![(3c^{4} - 5c^{6})^{2} = [3c^{4} ]^{2} - 2*3c^{4} *5c^{6} + [5c^{6}]^{2}=\\=9c^{8} -30c^{10} + 25c^{12}](https://tex.z-dn.net/?f=%283c%5E%7B4%7D%20-%205c%5E%7B6%7D%29%5E%7B2%7D%20%3D%20%5B3c%5E%7B4%7D%20%5D%5E%7B2%7D%20-%202%2A3c%5E%7B4%7D%20%2A5c%5E%7B6%7D%20%2B%20%5B5c%5E%7B6%7D%5D%5E%7B2%7D%3D%5C%5C%3D9c%5E%7B8%7D%20-30c%5E%7B10%7D%20%2B%2025c%5E%7B12%7D)
70º
It's a supplementary angle so 180º - 110º