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Lunna [17]
3 years ago
15

There are 3 red and 9 blue counters in a box. A counter is chosen and then replaced. If you did this 144 times, how many times w

ould you expect to get a blue?
Mathematics
1 answer:
anygoal [31]3 years ago
3 0
If you do it 144 times that is (3+9)*12
This means that 12 times 3 red and 9 blue counters will be chosen that means that 9 blue counters will be chosen 12 times. 9*12 is 108.
This means blue counters will be chosen 108 times.
This can be checked as 108/3 would give you the number of red counters which is 36 and 108+36 is 144 

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olganol [36]
<h3>Answer:  (x+1)(x+3)</h3>

===================================================

Explanation:

Let's assume it factors into (x+a)(x+b)

The goal is to find the two numbers a and b.

FOIL out (x+a)(x+b) to get x^2+(a+b)x+ab

Note how a+b is the middle term and ab is the last term.

In the original expression, 4 is the middle term and 3 is the last term.

So we need to find two numbers that

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There are two ways to multiply to 3 and they are

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Therefore (x+a)(x+b) = (x+1)(x+3)

And x^2+4x+3 = (x+1)(x+3)

8 0
3 years ago
Look at the triangle show on the right. The Pythagorean Theorem states that the sum of the squares of the legs of a right triang
Vladimir [108]

Answer:

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Step-by-step explanation:

Given

(\frac{b}{r})^2  + (\frac{a}{r})^2

Required

Use the expression to prove a trigonometry identity

The given expression is not complete until it is written as:

(\frac{b}{r})^2  + (\frac{a}{r})^2  = (\frac{r}{r})^2

Going by the Pythagoras theorem, we can assume the following.

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So, we have:

Sin\theta = \frac{a}{r}

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Having said that:

The expression can be further simplified as:

(\frac{b}{r})^2  + (\frac{a}{r})^2  = 1

Substitute values for sin and cos

(\frac{b}{r})^2  + (\frac{a}{r})^2  = 1 becomes

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3 0
3 years ago
When 18 is added to 6 times a certain number the result is 168. what is the number
Vlad1618 [11]
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3 0
3 years ago
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Grace starts with 100 milligrams of a radioactive substance. The amount of the
love history [14]

Answer:

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Step-by-step explanation:

8 0
3 years ago
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Ksenya-84 [330]
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