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2 years ago

What are the roots of the quadratic function f(b)=b^2-75

1 answer:

5 0

Set f(b) = b^2 - 75 = to 0 and solve for b:

b^2 = 75
b^2 = 25(3)
b = plus or minus sqrt(25[3]) = plus or minus sqrt(25)*sqrt(3) = plus or minus 5 sqrt(3).

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If 1m = 3.3ft, how many cubic feet is the Kuroshio Sea Tank? Show your calculations!

Daniel [21]

The kuroshio sea tank is 115.5 ft

6 0

2 years ago

There are two misshapen coins in a box; their probabilities for landing on heads when they are flipped are, respectively, .4 and

Leokris [45]

Answer:

E(X) = 6.0706

Step-by-step explanation:

1) Define notation

X = random variable who represents the number of heads in the 10 first tosses

Y = random variable who represents the number of heads in range within toss number 4 to toss number 10

And we can define the following events

a= The first coin has been selected

b= The second coin has been selected

c= represent that we have 2 Heads within the first two tosses

2) Formulas to apply

We need to find E(X|c) = ?

If we use the total law of probability we can find E(Y)

E(Y) = E(Y|a) P(a|c) + E(Y|b)P(b|c) ....(1)

Finding P(a|c) and using the Bayes rule we have:

P(a|c) = P(c|a) P(a) / P(c) ...(2)

Replacing P(c) using the total law of probability:

P(a|c) = [P(c|a) P(a)] /[P(c|a) P(a) + P(c|b) P(b)] ... (3)

We can find the probabilities required

P(a) = P(b) = 0.5

P(c|a) = (3C2) (0.4^2) (0.6) = 0.288

P(c|b) = (3C2)(0.7^2) (0.3) = 0.441

Replacing the values into P(a|c) we got

P(a|c) = (0.288 x 0.5) /(0.288x 0.5 + 0.441x0.5) = 0.144/ 0.3645 = 0.39506

Since P(a|c) + P(b|c) = 1. With this we can find P(b|c) = 1 - P(a|c) = 1-0.39506 = 0.60494

After this we can find the expected values

E(Y|a) = 7x 0.4 = 2.8

E(Y|b) = 7x 0.7 = 4.9

Finally replacing the values into equation (1) we got

E(Y|c) = 2.8x 0.39506 + 4.9x0.60494 = 4.0706

And finally :

E(X|c) = 2+ E(Y|c) = 2+ 4.0706 = 6.0706

6 0

2 years ago

Susan is attending a talk at her son's school. There are 8 rows of 10chairs where 54 parents are sitting. Susan notices that eve

kozerog [31]

Answer:

The largest possible number of adjacent empty chairs in a single row is 3

Step-by-step explanation:

The parameters given are;

The number of chairs = 8 × 10 = 80 chairs

The number of parents = 54

Sitting arrangements of parents = Alone or to one other person

Therefore;

The maximum number of parents on a row = 1 + 1 + 0 + 1 + 1 + 0 + 1 + 1 + 0 + 1 = 7

Hence when the rows have the maximum number of parents occupying the seats we have for the 8 rows;

7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 = 56

But there are only 54 parents, therefore, up to the 7th row will have 7 parents while the 8th row will have only 5 parents to make the possible sitting arrangement to be as follows;

7 + 7 + 7 + 7 + 7 + 7 + 7 + 5 = 54

The sitting arrangement for the 8th row is therefore

1 + 1 + 0 + 1 + 1 + 0 + 1 + 0 + 0 + 0

Hence there will be three empty seats in the 8th row making the largest possible number of adjacent empty chairs in a single row = 3.

4 0

2 years ago

For a recent season in college football, the total number of rushing yards for that season is recorded for each running back. Th

Galina-37 [17]

Answer:

The standard deviation of the number of rushing yards for the running backs that season is 350.

Step-by-step explanation:

Consider the provided information.

The mean number of rushing yards for the running backs that season is 790 yards. One running back had 1,637 rushing yards for the season, which is 2.42 standard deviations above the mean number of rushing yards.

Here it is given that mean is 790 and 1637 is 2.42 standard deviations above the mean.

Use the formula: $z=\frac{x-\mu}{\sigma}$