b) An achievement test was administered to a class of 20,000 students. The mean score was 80 and the standard deviation was 11. If Lingard scored 72 in the test, how many students did better than him

Answers:

a = 2

b = 3

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Explanation:

Plug in x = 0 and y = 2 to find that

y = a*b^x

2 = a*b^0

2 = a*1

2 = a

a = 2

Then plug in x = 3 and y = 54 to determine the value of b

y = a*b^x

y = 2*b^x

54 = 2*b^3

2b^3 = 54

b^3 = 54/2

b^3 = 27

b = (27)^(1/3)

b = 3

So we have y = a*b^x update to y = 2*3^x

Answer:

it is  D.

Step-by-step explanation:

Answer:

Step-by-step explanation:

Assuming the gravel reaches the top of the walls and no higher, the volume is 7×4×16 = 448 m³

Answer:

hello thereee

now vol of truck = l b h = 7 * 4 * 16 = 448 m^3

( 448m^3 is final ans...

glad for brainliest.... hope that helps <3

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Explanation:

Let y be the length of the vertical dashed red line in the drawing. More specifically, this dashed line is an altitude.

Along the top, the entire segment is 400 units long. The right piece is 144 units long, so the left piece is 400-144 = 256 units long.

The triangles are similar, allowing us to set up a proportion like so:

144/y = y/256

144*256 = y*y

36864 = y^2

y^2 = 36864

y = sqrt(36864)

y = 192

So this is the length of that vertical dashed red line.

--------------------------------

Now shift your attention solely on the smaller triangle on the right side. It is a right triangle with legs 144 and 192. The hypotenuse is x.

We can use the pythagorean theorem to find x.

a^2 + b^2 = c^2

c = sqrt( a^2 + b^2 )

x = sqrt( 144^2 + 192^2 )

x = 240

240.

Let y be the length of the vertical dashed red line in the drawing. More specifically, this dashed line is an altitude.

Along the top, the entire segment is 400 units long. The right piece is 144 units long, so the left piece is 400-144 = 256 units long.

The triangles are similar, allowing us to set up a proportion like so:

144/y = y/256

144*256 = y*y

36864 = y^2

y^2 = 36864

y = sqrt(36864)

y = 192

So this is the length of that vertical dashed red line.

Now shift your attention solely to the smaller triangle on the right side. It is a right triangle with legs 144 and 192. The hypotenuse is x.

We can use the Pythagorean theorem to find x.

a^2 + b^2 = c^2

c = sqrt( a^2 + b^2 )

x = sqrt( 144^2 + 192^2 )

x = 240

Pythagorean theorem, the well-known geometric theorem that the sum of the squares on the legs of a right triangle is equal to the square on the hypotenuse (the side opposite the right angle)—or, in familiar algebraic notation, a2 + b2 = c2.

Learn more about the Pythagorean theorem at

https://brainly.com/question/343682

#SPJ2

Answer:

y=3x

Step-by-step explanation:

-6/-2=3, -3/-1=3, 3/1=3. 6/2=3

Answer:

123.1 pounds is vary long, and I don't want to repeat, so 55.8372207 repeat.

Step-by-step explanation:

If you have any questions regarding my answer, tell me them in the comments, and I will come answer them for you. Have a good day.

Answer:

Step-by-step explanation:

34.375 Liters of milk make 11 tins of cheese. Assuming that milk is available in whole liters only, 35 Liters of milk are needed.

Answer:

Hello,

Answer C: -40

Step-by-step explanation:

[tex]\displaystyle \sum_{k=1}^4\ (-4k)\\\\=-4*\sum_{k=1}^4\ k\\\\=-4*4*\dfrac{1+4}{2} \\\\=-4*5*2\\\\=-40\\[/tex]

Let x be the first number in the sequence, so the first three numbers are

{x, 0.5x, 0.5²x}

Then

{x/4 + 10, 0.5x - 10, 2(0.5²x) + 10}

is arithmetic, so there is some constant c such that

0.5x - 10 = x/4 + 10 + c   ==>   x/2 - 10 = x/4 + 10 + c

2(0.5²x) + 10 = 0.5x - 10 + c   ==>   x/2 + 10 = x/2 - 10 + c

Solve the second equation for c :

x/2 + 10 = x/2 - 10 + c

c = 20

Substitute this into the first equation and solve for x :

x/2 - 10 = x/4 + 10 + 20

x/4 = 40

x = 160

Then the terms are

{160, 80, 40}

Step-by-step explanation:

Just use the Law of Indices.

Answer:

The equation of the parabola with a focus at (2,4) and a directrix of y=8 is,

48-8y=(x-2)²

Answer:

∠ A ≈ 79.0°

Step-by-step explanation:

Using the Cosine rule to find the angle

cosA = [tex]\frac{b^2+c^2-a^2}{2bc}[/tex]

        = [tex]\frac{15^2+29^2-30^2}{2(15)(29)}[/tex]

        = [tex]\frac{225+841-900}{870}[/tex]

        = [tex]\frac{166}{870}[/tex] , then

A = [tex]cos^{-1}[/tex] ([tex]\frac{166}{870}[/tex] ) ≈ 79.0° ( to the nearest tenth )

Answer:

15 cm

Step-by-step explanation:

Since the traingles are similar, we can find the ratio between the side lengths, and it will be the same for each side.

We can use the side length 9 and 15 to find this ratio. 15/9=5/3. So, the ratio of a side length of the larger triangle to the smaller one is 5/3, so our equation becomes 5/3 = 25/x. Use any method you like to find that x=15.

Hope this helped,

~cloud

Answer:

18 dimes and 1 nickle

Step-by-step explanation:

This is because 18 time 10 is 180 and one of 5 add it and this is $1.85

Remeber a dollar is 100 cents

Answer:

120

Step-by-step explanation:

720÷6

why?

becoz 6= 1+5

1 is the cosy of the chair

5 is the cost of the desk

Answer:

750,. is answer

I hope it helps

One mathematical idea I've always been curious about is "integration and derivation".

Integration is about assimilating different variables. Derivation is a mathematical process whereby a result is gotten from some initial assumptions.

Integration is used everyday in different aspects of our lives. For example, if a person is travelling from let's say point A to point B, the speed used by the person might vary but through integration, one can easily get the accurate speed.

Through the division of equations into smaller bits, once can use integration to get the answer that one seeks. Architect can use integration in building the right structures at the exact places where the structures fits.

Likewise derivatives can be used by businesses in assessing whether a profit or loss will be made for a particular transaction or sale of product.

You can read more on:

https://brainly.com/question/14295614

We are given a system of equations,

[tex]\begin{cases}-x+2y=0\\y=-2\\ \end{cases}[/tex]

This will translate into a 2x2 matrix of coefficients (because 2 equations and 2 unknowns),

[tex]\begin{bmatrix}-1&2\\0&1\\ \end{bmatrix}[/tex]

The matrix will then be applied to the vector (lower dimensions on top),

[tex]\begin{bmatrix}x\\y\\ \end{bmatrix}[/tex]

And the result vector will be whats on the other side of equals sign,

[tex]\begin{bmatrix}0\\-2\\ \end{bmatrix}[/tex]

So to put everything together,

[tex]\begin{bmatrix}-1&2\\0&1\\ \end{bmatrix}\begin{bmatrix}x\\y\\ \end{bmatrix}=\begin{bmatrix}0\\-2\\ \end{bmatrix}[/tex]

Hope this helps :)

Answer:

3/4

Step-by-step explanation:

There are 13 hearts in a 52 deck.

52-13=39

39/52=3/4

The probability that you are not dealt a heart from the deck of cards is 3/4.

Probability determines the chances that an event would occur. The probability the event occurs is 1 and the probability that the event does not occur is 0.

The probability that you are not dealth with a heart = 1 - (number of hearts / total number of cards)

1 - 13/52 = 39/52 =  3/4

To learn more about probability, please check: https://brainly.com/question/13234031

Answer:

Missing length = 12

Step-by-step explanation:

Let x represent the missing length.

Since the triangles are similar, ∆KLM ~ ∆KRS, therefore, the ratio of their corresponding side lengths would be the same. This implies that:

KL/KR = KM/KS

KL = 65

KR = 65 - 52

KR = 13

KM = 60

KS = x

Plug in the values

65/13 = 60/x

Cross multiply

65*x = 60*13

65x = 780

Divide both sides by 65

65x/65 = 780/65

x = 12

Answer:

Hello,

P(B)=0.65

Step-by-step explanation:

If P(A+B) means P(A∪B)=0.93 then you may read below.

Let's say x=P(B)

A and B being independent, P(A∩B)=P(A)*P(B)=0.8*x

Since P(A∪B)=P(A)+P(x)-P(A∩B) ,

0.93=0.8+x-0.8*x

0.2*x=0.13

x=0.65

Answer:

320/3

Step-by-step explanation:

First find the common ratio

20/80 = 1/4

The sum of an infinite geometric series

sum = a1/ (1-r)  where a1 is the first term and r is the common ratio

         =80/ ( 1-1/4)

         = 80/(3/4)

        = 80 *4/3

      = 320/3

Answer:

y = 2x + 1

Step-by-step explanation:

y = mx + c

m = slope = 2

y = 2x + c

sub x = 1, y = 3

3 = 2(1) + c

c = 1

Answer:

100091

Step-by-step explanation:

Answer:

(a)

[tex]\begin{array}{cccccc}x & {1} & {3} & {4} & {6} & {12} \ \\ P(x) & {0.30} & {0.10} & {0.05} & {0.15} & {0.40} \ \end{array}[/tex]

(b)

[tex]P(3 \le x \le 6) = 0.30[/tex]

[tex]P(4 \le x)=0.60[/tex]

Step-by-step explanation:

Given

[tex]F(x) = \left[\begin{array}{ccc}0& x<1 &\\0.30&1 \le x<3 &\\0.40&3 \le x < 4& &0.45 &4 \le x<6 &\\0.60 & 6 \le x < 12 & & 1 & 12 \le x\end{array}\right[/tex]

Solving (a): The pmf

This means that we list out the probability of each value of x.

To do this, we simply subtract the current probability value from the next.

So, we have:

[tex]\begin{array}{cccccc}x & {1} & {3} & {4} & {6} & {12} \ \\ P(x) & {0.30} & {0.10} & {0.05} & {0.15} & {0.40} \ \end{array}[/tex]

The calculation is as follows:

[tex]0.30 - 0 = 0.30[/tex]

[tex]0.40 - 0.30 = 0.10[/tex]

[tex]0.45 - 0.40 = 0.05[/tex]

[tex]0.60 - 0.45 = 0.15[/tex]

[tex]1 - 0.60 = 0.40[/tex]

The x values are gotten by considering where the equality sign is in each range.

[tex]1 \le x < 3[/tex] means [tex]x = 1[/tex]

[tex]3 \le x < 4[/tex] means [tex]x = 3[/tex]

[tex]4 \le x < 6[/tex] means [tex]x=4[/tex]

[tex]6 \le x < 12[/tex] means [tex]x = 6[/tex]

[tex]12 \le x[/tex] means [tex]x = 12[/tex]

Solving (b):

[tex](i)\ P(3 \le x \le 6)[/tex]

This is calculated as:

[tex]P(3 \le x \le 6) = F(6) - F(3-)[/tex]

From the given function

[tex]F(6)= 0.60[/tex]

[tex]F(3-) = F(1) = 0.30[/tex]

So:

[tex]P(3 \le x \le 6) = 0.60 - 0.30[/tex]

[tex]P(3 \le x \le 6) = 0.30[/tex]

[tex](ii)\ P(4 \le x)[/tex]

This is calculated as:

[tex]P(4 \le x)=1 - F(4-)[/tex]

[tex]P(4 \le x)=1 - F(3)[/tex]

[tex]P(4 \le x)=1 - 0.40[/tex]

[tex]P(4 \le x)=0.60[/tex]

Answer:

Sorry this is NWEA so I want you to try and figure it out on your own, hint: use subtraction.

Step-by-step explanation:

Answer:

In the picture below.

Step-by-step explanation:

From the commenter and answer above, confirmed on edge 2022.

Answer:

D)

DF = 52

AB = 48

Step-by-step explanation:

Use the two lengths of sides already given.

Divide to find the scale factor:

20 / 5 = 4

Scale factor: 4

Now multiply to find the unknown sides:

13 × 4  = 52

12 × 4 = 48

DF = 52

AB = 48

Hope this helped.