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Vlada [557]
3 years ago
7

In a popular tale of wizards and witches, a group of them finds themselves in a room with unmarked doors which change position,

making it impossible to determine which door is which when the room is entered or reentered. Suppose that there are 4 doors in the room. One door leads out of the building after 3 hours of travel. The second and third doors return to the room after 3.5 and 5 hours of travel, respectively. The fourth door leads to a dead end, the end of which is a 2.5 hour trip from the door.If the probabilities with which the group selects the doors are 0.2, 0.1, 0.2, and 0.5, respectively, what is the expected number of hours before the the group exits the building?E[Number of hours]=__________-
Mathematics
1 answer:
SSSSS [86.1K]3 years ago
7 0

Answer:

Expected number of hours before the the group exits the building = E[Number of hours] = 3.2 hours

Step-by-step explanation:

Expected value, E(X) is given as

E(X) = Σ xᵢpᵢ

xᵢ = each variable

pᵢ = probability of each variable

Let X represent the number of hours before exiting the building taking each door. Note that D = Door

D | X | P(X)

1 | 3.0 | 0.2

2 | 3.5 | 0.1

3 | 5.0 | 0.2

4 | 2.5 | 0.5

E(X) = (3×0.2) + (3.5×0.1) + (5×0.2) + (2.5×0.5) = 3.2 hours

Hope this Helps!!!

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Find the distance between the points (-1,-5) and (-10,7).
Paladinen [302]

Answer:

15 units

Step-by-step explanation:

Calculate the distance d using the distance formula

d = \sqrt{(x_{2}-x_{1})^2+(y_{2}-y_{1})^2    }

with (x₁, y₁ ) = (- 1, - 5) and (x₂, y₂ ) = (- 10, 7)

d = \sqrt{(-10+1)^2+(7+5)^2}

   = \sqrt{(-9)^2+12^2}

    = \sqrt{81+144}

    = \sqrt{225}

    = 15 units

5 0
2 years ago
The solutions to x2-5x-14=0 are what
Anvisha [2.4K]

Answer:

-2

Step-by-step explanation:

8 0
3 years ago
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Se quiere construir un muro de 4 m de alto, 12 m de largo y 10 cm de espesor. ¿Cuántos ladrillos de 8 cm de alto, 20 cm de largo
Llana [10]

Answer:

3000

Step-by-step explanation:

Let's start by finding the volume of the wall. The volumen of the wall can be considered as the volume of a rectangular prism. The volume of a rectangular prism is given by:

V_w=w*l*h\\\\Where:\\\\w=Width=10cm=0.1m\\l=Length=12m\\h=Height=4m

So the volume of the wall is:

V_w=0.1*12*4=4.8m^3

Now, we can find the volume of the brick using the same method since a brick can be considered as a rectangular prism as well:

V_b=w*l*h\\\\For\hspace{3}the\hspace{3}brick\\\\w=10cm=0.1m\\l=20cm=0.2m\\h=8cm=0.08m

Hence:

V_b=(0.1)*(0.2)*(0.08)=0.0016m^3

In order to know how many bricks are required to build the wall, we just need to fill the wall volume with the number of bricks of this volume. So:

V_w=nV_b\\\\Where\\\\n=Number\hspace{3}of\hspace{3}bricks

Solving for n:

n=\frac{V_w}{V_b} =\frac{4.8}{0.0016} =3000

Therefore, we need 3000 bricks to build that wall.

Translation:

Comencemos por encontrar el volumen del muro. El volumen del muro puede considerarse como el volumen de un prisma rectangular. El volumen de un prisma rectangular viene dado por:

V_w=w*l*h\\\\Donde:\\\\w=Espesor=10cm=0.1m\\l=Largo=12m\\h=Alto=4m

Entonces el volumen del muro es:

V_w=0.1*12*4=4.8m^3

Ahora, podemos encontrar el volumen del ladrillo utilizando el mismo método, ya que un ladrillo también puede considerarse como un prisma rectangular:

V_b=w*l*h\\\\Para\hspace{3}el\hspace{3}ladrillo\\\\w=10cm=0.1m\\l=20cm=0.2m\\h=8cm=0.08m

Por lo tanto:

V_b=(0.1)*(0.2)*(0.08)=0.0016m^3

Para saber cuántos ladrillos se requieren para construir el muro, solo necesitamos llenar el volumen del muro con la cantidad de ladrillos de este volumen. Entonces:

V_w=nV_b\\\\Donde\\\\n=Numero\hspace{3}de\hspace{3}ladrillos

Resolviendo para n:

n=\frac{V_w}{V_b} =\frac{4.8}{0.0016} =3000

Por lo tanto, necesitamos 3000 ladrillos para construir ese muro.

4 0
3 years ago
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marusya05 [52]

Answer:

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Step-by-step explanation:

as we know that

40 inch = 1 metre

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width of the tile = 4 inch = 4 / 40 = 0.1 metre

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1 metre = 100 cm

So, length of the tile = 0.2 m = 0.2 x 100 = 20 cm

width of the tile = 0.1 m = 0.1 x 100 = 10 cm  

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3 years ago
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Answer:

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