HELP PLEASE. URGENT TIMED QUIZ.

I have 10 goats, n of which are male. I need to choose 2 of them to make a casserole.

snow_tiger [21]

Answer: There are 4 male goats.

Step-by-step explanation:

We know that n of the 10 goats are male.

The probability that in a random selection, the selected goat is a male, is equal to the quotient between the number of male goats (n) and the total number of goats (10)

The probability is;

p = n/10

Now the total number of goats is 9, and the number of male goats is n -1

then the probability of selecting a male goat again is:

q = (n-1)/9

The joint probability (the probability that the two selected goats are male) is equal to the product of the individual probabilities, this is

P = p*q = (n/10)*((n-1)/9)

And we know that this probability is equal to 2/15

Then we have:

(n/10)*((n-1)/9) = 2/15

(n*(n-1))/90 = 2/15

n*(n-1) = 90*2/15 = 12

n^2 - n = 12

n^2 - n - 12 = 0

This is a quadratic equation, we can find the solutions if we use Bhaskara's formula:

For an equation:

a*x^2 + b*x + c = 0

The two solutions are given by:

$x = \frac{-b +- \sqrt{b^2 - 4*a*c} }{2*a}$

For our case, the solutions will be:

$n = \frac{1 +- \sqrt{(-1)^2 - 4*1*(-12)} }{2*1 } = \frac{1+- 7}{2}$

The two solutions are:

n = (1 - 7)/2 = -3 (this solution does not make sense, we can not have a negative number of goats)

The other solution is:

n = (1 + 7)/2 = 4

This solution does make sense, this means that we have 4 male goats.

5 0

2 years ago

The average number of employees that call in sick for the day over the course of a year is 25.

Georgia [21]

Answer:

24

Step-by-step explanation:

add all the numbers up and then divide that number by the amount of numbers there are

3 0

3 years ago

A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are defective. Step 2 of 2 :

const2013 [10]

Answer:

The 80% confidence interval for the population proportion of disks which are defective is (0.059, 0.079).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

Suppose a sample of 1067 floppy disks is drawn. Of these disks, 74 were defective.

This means that $n = 1067, \pi = \frac{74}{1067} = 0.069$

80% confidence level

So $\alpha = 0.2$ , z is the value of Z that has a pvalue of $1 - \frac{0.2}{2} = 0.9$ , so $Z = 1.28$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.069 - 1.28\sqrt{\frac{0.069*0.931}{1067}} = 0.059$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.069 + 1.28\sqrt{\frac{0.069*0.931}{1067}} = 0.079$

The 80% confidence interval for the population proportion of disks which are defective is (0.059, 0.079).

7 0

2 years ago

A lift holds no more than 1200 pounds. If you are rolling a cart that weighs 760 pounds, how much more can the elevator hold?

cluponka [151]

1200-760=440

Answer is 440

5 0

2 years ago

Help plzzz!! Find the slope through these pairs of points

Colt1911 [192]

We can use the formula y2-y1/x2-x1 to find the slope.

1. 2-(-15)/12-5 gives us 17/7. The slope is 17/7.

2. -5-(-20)/6-(-18) gives us 15/24. We can simplify this to 5/8. The slope is 5/8.

3. -19-(-19)/-17-(-18) is 0/1. The slope is 0.

4. -17-3/-11-(-1) is -20/-10. The slope is 2.

8 0

2 years ago