Perimeter of a triangle = all 3 sides added together
x + (x - 4) + (x - 4) = 19
3x - 8 = 19
3x = 19 + 8
3x = 27
x = 27/3
x = 9 <==
Answer:
x = 100
Step-by-step explanation:

I’m gonna say it’s a carrot
The probability that none of the four have been vaccinated is
(1-0.63)^4 = 0.01874161
The probability that at least one has been vaccinated is the complement of this,
≈0.9813
The answer for the expression is C.