Y = 1/3 x - 10 . . . (1)
2x + y = 4 . . . . . . (2)
Putting (1) into (2) gives, 2x + 1/3 x - 10 = 4
7/3 x - 10 = 4
7/3 x = 4 + 10 = 14
x = (3 x 14)/7 = 6
From (1), y = 1/3(6) - 10 = 2 - 10 = -8
x = 6, y = -8
8 goes into 72 and 8
72÷8=9
8÷8=1
Answer: 0.2224
Step-by-step explanation:
Given: The proportion of adults need eye correction: p= 78%=0.78
Let X be a binomial variable that represents the number of adults who need eye correction.
Sample size of adults: n= 12
Binomial ditsribution formula:
Now, the probability that at least 11 of them need correction for their eyesight will be
Hence, the required probability = 0.2224
The x-coordinate of the vertex of a parabola y = ax^2 + bx + c is x = -b / (2a).
Here, a = -3 and b = -10, so the x-coord of the vertex is x = 10 / (2*-3), or
x = 10 / (-6) = -5/3
and so the y-coordinate is y = -3(-5/3)^2 - 10(-5/3) = 25/3
The vertex of this parabola is (-5/3, 25/3). (answer)