STEP 1
Mean =

STEP 2
Subtract the mean from each data value then square the answer

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STEP 3
Add the squared answers in STEP 2 then find the mean

STEP 4
Square root the answer in STEP 3

Standard deviation is 236.5
The Answer is Triangular Prism.
The answer is B, all real number
8x would represent multiplying 8(people) times x(ticket cost) But you don't know how much the tickets cost per person so that's why it's x.
8x + 20 = 76
76-20=56
56÷8=7
x equals 7