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2 years ago

Let A and B be two disjoint events such that P(A) = 0.47 and P(B) = 0.3. What is P(A or B)?

Mathematics

2 answers:

Alchen [17]2 years ago

6 0

<h3>Answer: 0.77</h3>

Work Shown:

P(A or B) = P(A) + P(B)

P(A or B) = 0.47 + 0.30

P(A or B) = 0.77

Notes:

The formula only works if A and B are disjoint, aka mutually exclusive
If A and B are not disjoint, then use this formula: P(A or B) = P(A) + P(B) - P(A and B)

GrogVix [38]2 years ago

4 0

Answer:

P(A or B) = 0.77

Step-by-step explanation:

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The left and right page numbers of an open book are two consecutive integers whose sum is 23. Find these page number.

zavuch27 [327]

Answers: The page numbers are 11 and 12

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

Explanation:

Consecutive integers are ones that follow immediately after another. For example, the set {7,8,9,10} are consecutive.

Let,

x = first page, some positive whole number
x+1 = second page, follows immediately after page x

Adding those two said pages will lead to 23

first + second = 23

(x) + (x+1) = 23

2x+1 = 23

2x = 23-1

2x = 22

x = 22/2

x = 11 is the first page

x+1 = 11+1 = 12 is the second page

Check: 11+12 = 23 which confirms the answers.

8 0

2 years ago

A report by the US Geological Survey indicates that glaciers in Glacier National Park, Montana, are shrinking. Recent estimates

postnew [5]

Answer

a) C

b) B

c) C, E

d) 15.5

e) 0.7

f) 67.7

Step-by-step explanation

a) A linear equation can be written as $y=mx+c$ where $m$ is the slope and $c$ is the intercept on the $y$ -axis. The slope describes how $y$ changes when $x$ changes. A negative value means the it is a decreasing change. In our case, $y$ is $A$ and $x$ is $t$ . Thus, the slope of the equation is $m=-0.062$ . This means that the area of glacier is decreasing by $0.062 \text{km}{}^2 = 62000 \text{m}{}^2$ every year since 2000.

b) The $A$ -intercept (= 16.2 $\text{km}{}^2$ ) represents the area covered when $t=0$ . But $t=0$ starting from year 2000. This intercept then represents the area covered by glacier in the year 2000. Therefore, the area covered by glacier in 2000 was 16.2 $\text{km}{}^2$ .

c) $A=f(t)$ means the area covered after year 2000. Setting it to 12 means the area covered after $t$ years is 12 $\text{km}{}^2$ ). $t$ is therefore the number of years since 2000 that the total area covered will be 12 $\text{km}{}^2$ ).

d) $f(12)=16.2−0.062\times12 =16.2-0.744 = =15.456 15.5 \text{km}{}^2$ to 1 decimal place.

e) The term involving $t$ represents the disappearing area. In 12 years, the disappeared area is $0.062\times12=0.744 =0.7 \text{km}{}^2$ to 1 decimal place.