What must be true in order for P (A or B) = P(A) + P (B)?

2 answers:

7 0

A and B must be disjoint<span> in order </span>for P (A or B) = P (A) + P (B). I am hoping that this answer has satisfied your query and it will be able to help you, and if you would like, feel free to ask another question.

snow_tiger [21]3 years ago

6 0

For the equation to be true, the events A and B must be mutually exclusive.

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3 years ago

If the cost of a dozen eggs rises from .99 to 1.34 what is the percent of the increase

Amiraneli [1.4K]

To find the percent of increase get the difference between the prices and then divided by the oringinal price and then time that by 100

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3 years ago

1)a chord of length 18cm midway the radius of a circle. calculate the radius of the circle correct to 1d.p. 2)if two parallel ch

kykrilka [37]

Part 1:

Given that the length of the chord is 18 cm and the chord is midway the radius of the circle.

Thus, half the angle formed by the chord at the centre of the circle is given by:

$\cos\theta=\frac{\left( \frac{1}{2} r\right)}{r}= \frac{1}{2} \\ \\ \Rightarrow\theta=\cos^{-1}\left( \frac{1}{2} \right)=60^o$

Now,

$\sin60^o= \frac{9}{r} \\ \\ \Rightarrow r= \frac{9}{\sin60^o} =10.392$

Therefore, the radius of the circle is 10.4 cm to 1 d.p.

Part 2I:

Given that the radius of the circle is 10 cm and the length of chord AB is 8 cm. Thus, half the length of the chord is 4cm. Let the distance of the mid-point O to /AB/ be x and half the angle formed by the chord at the centre of the circle be θ, then

$\sin\theta= \frac{4}{10} = \frac{2}{5} \\ \\ \theta=\sin^{-1}\left( \frac{2}{5} \right)=23.6^o$

Now,

$\cos23.6^o= \frac{x}{10} \\ \\ \Rightarrow x=10\cos23.6^o=9.165\approx9.2cm$

Part 2II:

Given that the radius of the circle is 10cm and the angle distended is 80 degrees. Let half the length of chord CD be y, then:

$\sin40^o= \frac{y}{10} \\ \\ \\ \Rightarrow y=10\sin40^o=6.428$

Thus, the length of chord CD = 2(6.428) = 12.856 which is approximately 12.9 cm.

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Yuliya22 [10]

I think the answer is A.......

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3 years ago

How do I write an algebraic expression for the amount of money (in dollars) in N nickels minus 7 dollars?

Dominik [7]

Nickels are only worth $0.05 so:

m=0.05n-7

8 0

3 years ago

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