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3 years ago

Sam drove for 2 hours at 45 mph. He has the same distance remaining. How fast should he drive to make his average speed 60 mph?

1 answer:

8 0

Speed (S) = Distance (D) / time (t)

First stretch

45 = D / 2

D = 45*2

D = 90 mp

How is the same distance:

Second stretch

S = 90 / t

Average speed (AS):

AS = (S1+S2) / 2

60 = [45+(90/t)] / 2

120 = 45+90/t

120-45 = 90/t

75 = 90/t

t = 90/75

t = 1,2 h

________________________

And now:

S = 90 / t

S = 90 / 1,2

S = 75 mph

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F (x) = -x2 + 8x - 11 h(x) = -x-7 find f (9) + (-14)

bixtya [17]

Is there a answer choice of -5

5 0

2 years ago

Create the f(x) function based on the table. Your answer should be in function notation. X f(x) - 10 -6 -9 -5 1-8 -4 -7 1-3 5 9

Minchanka [31]

Answer:

$f(x) = x + 4$

Step-by-step explanation:

First create an equation in slope-intercept form, y = mx + b. To do this, find the rate of change or slope (m), and the y-intercept (b).

Using two pairs, (-7, -3) and (-8, -4),

$slope (m) = \frac{y_2 - y_1}{x_2 - x_1} = \frac{-4 -(-3)}{-8 -(-7)} = \frac{-1}{-1} = 1$

m = 1

To find b, substitute m = 1, x = -7 and y = -3 into y = mx + b.

Thus:

-3 = (1)(-7) + b

-3 = -7 + b

-3 + 7 = b

4 = b

b = 4.

Replace y with f(x), m with 1 and b with 4 in y = mx + b.

The function would be:

$f(x) = x + 4$

6 0

2 years ago

A particular sale involves four items randomly selected from a large lot that is known to contain 9% defectives. Let X denote th

umka2103 [35]

Answer:

The expected repair cost is $3.73.

Step-by-step explanation:

The random variable X is defined as the number of defectives among the 4 items sold.

The probability of a large lot of items containing defectives is, p = 0.09.

An item is defective irrespective of the others.

The random variable X follows a Binomial distribution with parameters n = 9 and p = 0.09.

The repair cost of the item is given by:

$C=3X^{2}+X+2$

Compute the expected cost of repair as follows:

$E(C)=E(3X^{2}+X+2)$

$=3E(X^{2})+E(X)+2$

Compute the expected value of X as follows:

$E(X)=np$

$=4\times 0.09\\=0.36$

The expected value of X is 0.36.

Compute the variance of X as follows:

$V(X)=np(1-p)$

$=4\times 0.09\times 0.91\\=0.3276\\$

The variance of X is 0.3276.

The variance can also be computed using the formula:

$V(X)=E(Y^{2})-(E(Y))^{2}$

Then the formula of $E(Y^{2})$ is:

$E(Y^{2})=V(X)+(E(Y))^{2}$

Compute the value of $E(Y^{2})$ as follows:

$E(Y^{2})=V(X)+(E(Y))^{2}$

$=0.3276+(0.36)^{2}\\=0.4572$

The expected repair cost is:

$E(C)=3E(X^{2})+E(X)+2$

$=(3\times 0.4572)+0.36+2\\=3.7316\\\approx 3.73$

Thus, the expected repair cost is $3.73.

4 0

2 years ago

Can y’all please answer this question

USPshnik [31]

Answer:

The customer will pay $19

Option B is correct.

Step-by-step explanation:

Price of Ham per pound = $5.99

Price of Turkey per pound = $4.99

Price of Roast beef per pound = $6.99

Price of Salami per pound = $2.99

Price of Bologna per pound = $3.99

Customer purchased:

Ham = $\frac{1}{4}$ pound

Turkey = $1\frac{1}{2}=\frac{3}{2}$ pound

Roast beef = 1 pound

Bologna = $\frac{3}{4}$ pound

We will multiply the pound purchased with per pound price and add them to find the total cost.

The customer will pay :

$\frac{1}{4}\times5.99+\frac{3}{2} \times4.99+1\times6.99+\frac{3}{4}\times3.99$

$=1.4975+7.485+6.99+2.9925\\=18.965\\\approx19$

So, the customer will pay $19

Option B is correct.

5 0

2 years ago

Find the value of x 18 20 x

sesenic [268]

21 420 69 thank you very much

4 0

2 years ago