Answer:
If 0.2 = 20%, The probability that 1 person will be infected is 100%, according to theory.
I don't have a clue what this a0 at the right stands for, but if we neglected it, we can solve the problem.

So the answer would be 25.
Hope this helps.
Answer:
A≈32
ft²
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To find the surface area of a right rectangular prism you must use this formula A=2(wl+hl+hw)
Then plug in your variebles
A=2( 1.33*1.5+5+1.5+5+1.33)
This comes out to be A≈32 
Simple you just solve for y and put the equation in slope-intercept form