• A neighborhood threw a fireworks celebration for the 4th of July. A bottle rocket was launched upward from the ground with an
2 answers:
You might be interested in
Answer:
(a) 283 days
(b) 248 days
Step-by-step explanation:
The complete question is:
The pregnancy length in days for a population of new mothers can be approximated by a normal distribution with a mean of 268 days and a standard deviation of 12 days. (a) What is the minimum pregnancy length that can be in the top 11% of pregnancy lengths? (b) What is the maximum pregnancy length that can be in the bottom 5% of pregnancy lengths?
Solution:
The random variable <em>X</em> can be defined as the pregnancy length in days.
Then, from the provided information .
(a)
The minimum pregnancy length that can be in the top 11% of pregnancy lengths implies that:
P (X > x) = 0.11
⇒ P (Z > z) = 0.11
⇒ <em>z</em> = 1.23
Compute the value of <em>x</em> as follows:
Thus, the minimum pregnancy length that can be in the top 11% of pregnancy lengths is 283 days.
(b)
The maximum pregnancy length that can be in the bottom 5% of pregnancy lengths implies that:
P (X < x) = 0.05
⇒ P (Z < z) = 0.05
⇒ <em>z</em> = -1.645
Compute the value of <em>x</em> as follows:
Thus, the maximum pregnancy length that can be in the bottom 5% of pregnancy lengths is 248 days.
Hi there!
• f(x) = 3x + 1
• g(x) = x² - 6
Then,
According to th' question :-
(f - g)(x) = f(x) - g(x)
= 3x + 1 - (x² - 6)
= 3x + 1 - x² + 6
= -x² + 3x + 7
Hence,
Option 2ⁿᵈ : -x² + 3x + 7 is Correct.
~ Hope it helps!
• f(x) = 3x + 1
• g(x) = x² - 6
Then,
According to th' question :-
(f - g)(x) = f(x) - g(x)
= 3x + 1 - (x² - 6)
= 3x + 1 - x² + 6
= -x² + 3x + 7
Hence,
Option 2ⁿᵈ : -x² + 3x + 7 is Correct.
~ Hope it helps!
Answer:
- hits the ground at x = -0.732, and x = 2.732
- only the positive solution is reasonable
Step-by-step explanation:
The acorn will hit the ground where the value of x is such that y=0. We can find these values of x by solving the quadratic using any of several means.
__
<h3>graphing</h3>The attachment shows a graphing calculator solution to the equation
-3x^2 + 6x + 6 = 0
The values of x are -0.732 and 2.732. The negative value is the point where the acorn would have originated from if its parabolic path were extrapolated backward in time. Only the positive horizontal distance is a reasonable solution.
__
<h3>completing the square</h3>We can also solve the equation algebraically. One of the simplest methods is "completing the square."
-3x^2 +6x +6 = 0
x^2 -2x = 2 . . . . . . . . divide by -3 and add 2
x^2 -2x +1 = 2 +1 . . . . add 1 to complete the square
(x -1)^2 = 3 . . . . . . . . written as a square
x -1 = ±√3 . . . . . . . take the square root
x = 1 ±√3 . . . . . . . add 1; where the acorn hits the ground
The numerical values of these solutions are approximately ...
x ≈ {-0.732, 2.732}
The solutions to the equation say the acorn hits the ground at a distance of -0.732 behind Jacob, and at a distance of 2.732 in front of Jacob. The "behind" distance represents and extrapolation of the acorn's path backward in time before Jacob threw it. Only the positive solution is reasonable.
