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3 years ago

The ratio of boys to girls at a school is 9 to 11. If 400 students attend the school, how many are girls?

Mathematics

2 answers:

pentagon [3]3 years ago

6 0

Total ratio=9+11=20
number of girls=11/20*400
=220

xxTIMURxx [149]3 years ago

3 0

Answer: 220

Step-by-step explanation:

Given : The ratio of boys to girls at a school is 9 to 11.

Let the number of boys be 9x and the number of girls be 11x.

Since there are 400 students attend the school.

Then we have the following equation :-

$9x+11x=400\\\\\Rightarrow\ 20x=400\\\\\Rightarrow\ x=\dfrac{400}{20}=20$

Now, the number of girls = 11x = 11(20)=220

Hence, there are 220 girls.

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Answer:

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Step-by-step explanation:

Let's write the left hand side as a negative power, and 9 as a power of 3:

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2 years ago

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Given the right triangle below what is x?

lions [1.4K]

Answer:

B 10.8 or

A 9.2 depending on what side of the triangle is "x".

Step-by-step explanation:

we cannot see the triangle and which side is which. you forgot to show us the picture (or describe it in more detail).

but I assume that "x" would be the Hypotenuse (the baseline of the right triangle, the side opposite of the 90 degree angle).

then by using Pythagoras

c² = a² + b²

x² = 10² + 4² = 116

x = sqrt(116) = 10.8

but if x is any of the other sides (and not the Hypotenuse), then you need to adapt the calculation.

for example, if the Hypotenuse is the side with 10, then Pythagoras' formula would look like this

10² = x² + 4²

x² = 10² - 4² = 84

x = sqrt(84) = 9.2 (and answer A would be correct).

or if the Hypotenuse is the side with 4, then

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3 years ago

A standard deck of cards contains 52 cards. The cards have 4 different suits: clubs, diamonds, hearts, and spades. For each suit

Taya2010 [7]

Answer:

a. 108336, b. 480200

Step-by-step explanation:

a. No. of ace cards = 4

No. of non ace cards= 48

We draw 5 cards

So,

No. of ways of 2 aces = C(4,2) C(48,3)

No. of ways of 3 aces = C(4,3) C(48,2)

No. of ways of 4 aces = C(4,4) C(48,1)

Hence

No. of ways of 2 or more aces

= C(4,2) + C(48,3) + C(48,3) + C(4,3)C(48,2) +C(4,4)C(48,1)

= 6(17296) + 4(1128) + (48)

= 108336

b. No of ways any 5 cards can be chosen = C(52,5)

No. of ways kings of diamonds or queen of hearts is chosen = C(50,5)

Hence

No. of ways of choosing king of diamonds, queen of hearts or both = C(52,5) – C(50,5)

= 480200

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3 years ago

Agatha is five times older than her son bob. three years ago she was nine times older. how old is agatha?

Naya [18.7K]

Write an equation system based on the problem
"Agatha is five times older than her son, Bob" could be written as:
a = 5b.......(first equation)
"Three years ago, she was nine times older" could be written as:
a - 3 = 9(b - 3)......(second equation)

Solve the equation system
To find the value of b, substitute 5b as a to the second equation
a - 3 = 9(b - 3)
5b - 3 = 9(b - 3)
5b - 3 = 9b - 27
5b - 9b = -27 + 3
-4b = -24
b = -24/-4
b = 6
Her son, Bob, is 6 years old

To find Agatha's age, substitute the value of b to the first equation
a = 5b
a = 5 × 6
a = 30
Agatha is 30 years old

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3 years ago

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3 years ago

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