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 in order 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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Find the 6th term of a geometric sequence t3 = 444 and t7 = 7104. So I have to find r. But is this right: 7104 = 444r^4 r^4 = 16

galben [10]

Third term = t3 = ar^2 = 444 eq. (1)

Seventh term = t7 = ar^6 = 7104 eq. (2)

By solving (1) and (2) we get,

ar^2 = 444

=> a = 444 / r^2 eq. (3)

And ar^6 = 7104

(444/r^2)r^6 = 7104

444 r^4 = 7104

r^4 = 7104/444

= 16

r2 = 4

r = 2

Substitute r value in (3)

a = 444 / r^2

= 444 / 2^2

= 444 / 4

= 111

Therefore a = 111 and r = 2

Therefore t6 = ar^5

= 111(2)^5

= 111(32)

= 3552.

Therefore the 6th term in the geometric series is 3552.

8 0

2 years ago

A construction company built a scale model of a building. The model was built using a scale of 3 inches = 32 feet. If the buildi

Vlad1618 [11]

Let x represent the height of the model.

We have been given that a construction company built a scale model of a building. The model was built using a scale of 3 inches = 32 feet. We are asked to find the height of the model, if the building is expected to be 200 feet tall.

We will use proportions to solve our given problem as:

$\frac{\text{Model height}}{\text{Actual height}}=\frac{\text{Model length}}{\text{Actual length}}$