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3 years ago

BRAINLIEST ASAP! PLEASE HELP ME :)

Mathematics

1 answer:

aleksandrvk [35]3 years ago

5 0

Answer:

Two

Step-by-step explanation:

The table is saying that, if Sandra swam enough races, she should expect to get 20 firsts, 12 seconds, 6 thirds, and two no placements.

Her expected value of points will be the average (mean) of all the points awarded for each race.

The average is the total number of points divided by the number of races.

$\begin{array}{cccl}\textbf{Points} & & \textbf{Total}\\\textbf{Awarded} & \textbf{Frequency} & \textbf{Points}\\3 & 20 & 60\\2 & 12 & 24\\1 & 6 & 6\\0 & 2 & 0\\\textbf{TOTAL} & \mathbf{40} & \mathbf{90}\\\end{array}$

The simulation says that, if she swam 40 races, she should expect to earn a total of 90 points.

$\text{Average} = \dfrac{\text{Total points}}{\text{Number of races }} = \dfrac{\text{90}}{\text{40}} =\textbf{2.25 points/race}$

She can't win a fraction of a point, so she can expect to win two points in her first race.

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50 students live in a dormitory. The parking lot has the capacity for 30 cars. Each student has a car with probability 12 , inde

Maurinko [17]

Answer:

P(X is greater than 30) = 0.06

Step-by-step explanation:

Given that:

Sample proportion (p) = 0.5

Sample size = 30

The Binomial can be approximated to normal with:

$\mu = np = 50 \times 0.5 \\ \\ \mu= 25$

$\sigma = \sqrt{np(1-p) } \\ \\ \sigma = \sqrt{50 \times (0.5)(1-0.5) } \\ \\ \sigma = 3.536$

To find:

P(X> 30)

So far we are approximating a discrete Binomial distribution using the continuous normal distribution. 30 lies between 29.5 and 30.5

Normal distribution:

x = 30.5, $\mu$ = 25, $\sigma$ = 3.536

Using the z test statistics;

$z = \dfrac{x - \mu}{\sigma}$

$z = \dfrac{30.5 - 25}{3.536}$

$z = \dfrac{5.5}{3.536}$

z = 1.555

The p-value for P(X>30) = P(Z > 1.555)

The p-value for P(X>30) = 1 - P (Z< 1.555)

From the z tables;

P(X> 30) = 1 - 0.9400

Thus;

P(X is greater than 30) = 0.06

7 0

2 years ago

3x+4y-3z=4;5x-y+2z=3;x+2y-z=-2 Solving Systems in three variables

Harlamova29_29 [7]

Answer: x = 3, y = 1, z = 2

Step-by-step explanation:

EQ 1: x - y - z = 0

EQ 3: -x + 2y + z = 1

y = 1

EQ 2: 2x - 3y + 2z = 7 → 1(2x - 3y + 2z = 7) → 2x - 3y + 2z = 7

EQ 3: -x + 2y + z = 1 → -2( -x + 2y + z = 1) → -2x + 4y + 2z = 2

y + 4z = 9

y = 1 ⇒ 1 + 4z = 9

4z = 8

z = 2

Input y = 1 and z = 2 into one of the equations to solve for x:

EQ 1: x - y - z = 0

x - (1) - (2) = 0

x - 3 = 0

x = 3

Check:

EQ 2: 2x - 3y + 2z = 7

2(3) - 3(1) + 2(2) = 7

6 - 3 + 4 = 7

3 + 4 = 7

7 = 7 $\checkmark$

6 0

2 years ago

so on khan academy we have this question and it makes NO SINCE! it says "start with the number 2380. divide by 10. the number wi

grigory [225]

Answer:

B) Hundreds

Step-by-step explanation:

2380 ÷ 10 = 238

The number 238 is in the hundreds as the first digit is in the hundreds. You can tell because you say "two hundred."

Hope this helps

7 0

3 years ago

Determine a área total e perímetro da figura a seguir: Apresente os cálculos.

ra1l [238]

Answer:

Área: 6x2=12, 2x3=6, 10x3=30, 30+6+12=48; área = 48

Perímetro: 10+3+6+2+6+5+2+3+2+3=42; perímetro = 42

6 0

2 years ago

8(6g- 5h+8) I need help.

motikmotik

Answer:

The answer is 48g-40h+64

5 0

2 years ago