The function:
f ( x ) = x * 0.965^t
where x is the initial amount and t is the number of the years
80 = x * 0.965^3
80 = x * 0.89632
x = 80 : 0.89632 ≈ 89
Answer:
The initial amount of animals was 89.

3 0

3 years ago

Mandy and Pete have a biased spinner numbered 1, 2, 3, 4, 5. They each want to find an estimate for the probability that the spi

kotykmax [81]

Answer:

Pete

Step-by-step explanation:

Given that:

Mandy's Estimate :

Number of spins , n = 20

Pete's Estimate:

Number of spins, n = 200

A good probability estimate is one which has narrow margin of error with a high degree of confidence. These two variables are affected by sample size.

A high sample size give a narrower margin of error and increases the confidence level probability

Based on the sample size used by each of Pete and Mandy, we can conclude that, Pete's probability estimate would be better due to its significantly higher sample size.

5 0

3 years ago

Solve This Using The Quadratic Formula: 3x^2+9x-6=0

aivan3 [116]

<h3>Therefore either $x = \frac{-3+\sqrt{17}}{2}$ or, $x = \frac{-3-\sqrt{17}}{2}$ </h3>

Step-by-step explanation:

$3x^2 +9x -6=0$ $x = \frac{-b\pm\sqrt{b^2- 4ac} }{2a}$

$\Leftrightarrow x = \frac{-9\pm\sqrt{9^2- 4.3(-6)} }{2.3}$ here a = 3 ,b = 9 and c= -6

$\Leftrightarrow x = \frac{-9\pm\sqrt{153} }{6}$

$\Leftrightarrow x = \frac{3(-3\pm\sqrt{17}) }{6}$

$\Leftrightarrow x = \frac{-3\pm\sqrt{17}}{2}$

Therefore either $x = \frac{-3+\sqrt{17}}{2}$ or, $x = \frac{-3-\sqrt{17}}{2}$

4 0

3 years ago

Can someone please help me with 21-24 and explain/ show how you got the answer?

oksano4ka [1.4K]

The solution (x,y) needs to work in both equations. With multiple choice you can do guess and test method. Otherwise you need to combine the two equations into one by substitution or elimination methods.

21. substitution works well here since one equation is y= x+3. you can easily substitute the (x+3) for y in the other equation.
2x + (x+3) = -6
3x + 3 = -6
3x = -9
x = -3
use this in either equation to find y.
y = (-3)+3
solution: (-3,0)

22. these both equal y so they equal each other.
4x - 1 = 3x +6
4x - 3x = 6 + 1
x = 7
use this in either equation to find y
y = 4(7) - 1
y = 28 - 1
y = 27
solution: (7,27)

23. one equation is y = 2x - 3. So substitute (2x -3) for y in the other equation.
4x = 2(2x - 3) + 6
4x = 4x - 6 + 6
4x = 4x
x = x
any solution will work, infinitely many.

24. infinitely many solutions means the two equations are the same equation. Like the previous one they didn't look the same but if you put them both in terms of y...
y= 2x-3
4x = 2y + 6
4x - 6 = 2y
(4x - 6)/2 = y
2x - 3 = y
same equation.

from the image, I can't see all options but A & C do not look like the same equations. It's got to be either B or D.

3 0

3 years ago