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3 years ago

There are 20 people in Susan’s class. Each person gives a card to everyone else in the class. How many cards were exchanged?

Mathematics

2 answers:

Marianna [84]3 years ago

6 0

Each student will give 19 cards so 20x19=380

qwelly [4]3 years ago

5 0

Every person in the class gives 19 cards
⇒20*19=380 card were exchanged

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GarryVolchara [31]

Answer:

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Step-by-step explanation:

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3 years ago

En una hoja de papel cuyo perímetro es de 96 centímetros, se quiere imprimir un volante de manera que el área impresa sea un rec

elixir [45]

Answer:

El perímetro de la región impresa es 72 cm y su área es 288 cm².

Step-by-step explanation:

1. Tenemos el perímetro de la hoja de papel:

P₁ = 96 cm = 2l₁ + 2a₁ (1)

Como sabemos el margen superior, inferior, izquierdo y derecho podemos encontrar la relación entre el largo y ancho del rectángulo interno (región impresa) con el largo (l) y ancho (a) del rectángulo externo (hoja de papel):

$l_{2} = l_{1} - (m_{s} + m_{i}) = l_{1} - (3 cm + 2 cm) = l_{1} - 5 cm$ (2)

$a_{2} = a_{1} - (m_{d} + m_{iz}) = a_{1} - (2 cm + 5 cm) = a_{1} - 7 cm$ (3)

El perímetro del rectángulo interno es:

$P_{2} = 2l_{2} + 2a_{2}$ (4)

Introduciendo la ecuación (2) y (3) en (4):

$P_{2} = 2l_{2} + 2a_{2} = 2(l_{1} - 5 cm) + 2(a_{1} - 7 cm) = 2l_{1} + 2a_{1} - 10 cm - 14 cm = 96 cm - 24 cm = 72 cm$

Por lo tanto el perímetro del rectángulo interno (región impresa) es 72 cm.

2. Ahora para encontrar el área rectángulo interno debemos encontrar el largo y ancho del mismo, sabiendo que:

$l_{2} = 2a_{2}$ (5)

Introduciendo (5) en (4):

$P_{2} = 2l_{2} + 2a_{2} = 2*2a_{2} + 2a_{2} = 6a_{2}$

$a_{2} = \frac{P_{2}}{6} = \frac{72 cm}{6} = 12 cm$

$l_{2} = 2a_{2} = 2*12 cm = 24 cm$

Entonces el área es:

$A_{2} = l_{2}*a_{2} = 12 cm*24 cm = 288 cm^{2}$

Por lo tanto el área del rectágulo interno (región impresa) es 288 cm².

Espero que te sea de utilidad!

7 0

3 years ago

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omeli [17]

4/3 — 1/3 equals 3/3

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3 years ago

#3 Q. the diagrams solve please

olya-2409 [2.1K]

Its the first one, 22.5. This is because... if you multiply 5 and 4, you would get 20, the area of the square. You then have to multiply 1 and 5 to get 5 and divide it by 2 to get the area of the triangle which would be 2.5, then add 2.5 to 20 and get 22.5.
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4 years ago

Read 2 more answers

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Darya [45]

203.2 mm is ur answer

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3 years ago