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2 years ago

If a point in the figure below is chosen at random, what is the probability that it is in the shaded region?

Mathematics

1 answer:

Xelga [282]2 years ago

3 0

Answer:

254/324 which is about 78.4%

Step-by-step explanation:

found area of entire square to be 18² or 324

found area of 4-quarter circles - which equals one circle with radius of 9

A = 81π which is about 70

subtracted 324 and 70 to get 254

ratio of shaded to unshaded is 254 : 324

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The sum of the digits of a 2-digit number is 10. If 18 is added to the number, the digits of the new number are those of the ori

Aliun [14]

Answer:

Step-by-step explanation:

Let $(ab)$ represent a number with $a$ in the ten's position and $b$ is the one's position.

This means $(ab)$ actually has value of $10a+b$ .

We are given the sum of those digits of $(ab)$ is 10; this means $a+b=10$ .

It says if 18 is added to the number $(ab)$ , then the result is $(ba)$ .

So $(ab)$ has value $10a+b$ and

$(ba)$ has value $10b+a$ .

We are given then:

$(ab)+18=(ba)$

$10a+b+18=10b+a$

Subtract $10a$ on both sides:

$b+18=10b+a-10a$

Simplify:

$b+18=10b-9a$

Subtract $b$ on both sides:

$18=10b-b-9a$

$18=9b-9a$

Divide both sides by 9:

$2=b-a$

Rearrange by commutative property:

$2=-a+b$

So the system of equations we want to solve is:

$a+b=10$

$-a+b=2$

-------------------------Add equations together (this will eliminate the variable $a$ and allow you to go ahead and solve for $b$ :

$0+2b=12$

$2b=12$

Divide both sides by 2:

$b=\frac{12}{2}$

Simplify:

$b=6$

If $b=6$ and $a+b=10$ , then $a=4$ . $a=4$ since 4+6=10.

So the original number is (46).

18 more than 46 is 18+46=(64) which is what we wanted.

We also have the sum of 4 and 6 is 10 as well.

7 0

4 years ago

the half-life of strontium-90 is approximately 29 years. how much of a 500 g sample of strontium-90 will remain after 58 years

Yuliya22 [10]

Answer: 125 g

<u>Step-by-step explanation:</u>

$A = P_o\cdot e^{kt}\\\\\text{First, use the given information to find k:}\\\\\bullet A=\dfrac{1}{2}P_o\\\\\bullet k = unknown\\\\\bullet t=29\text{ years}\\\\\dfrac{1}{2}P_o=P_o\cdot e^{k(29)}\\\\\\\dfrac{1}{2}=e^{k(29)}\qquad divided\ both\ sides\ by\ P_o\\\\\\ln\bigg(\dfrac{1}{2}\bigg)=ln\bigg(e^{k(29)}\bigg)\qquad applied\ ln\ to\ both\ sides\\\\\\ln\bigg(\dfrac{1}{2}\bigg)=29k\qquad simplified-ln\ and\ e\ cancel\ out\\\\\\\dfrac{ln\bigg(\dfrac{1}{2}\bigg)}{29}=k\qquad divided\ 29\ from\ both\ sides\\\\\\-0.0239=k$

$\text{Now, use the following in the equation to solve for A:}\\\\\bullet A=unknown\\\bullet P_o=500\\\bullet k=-0.0239\\\bullet t=58\text{ years}\\\\A=500\cdot e^{(-0.0239)(58)}\\\\.\quad=500\cdot e^{-1.386}\\\\.\quad=125$

8 0

3 years ago

05.02 LC)

nikklg [1K]

Answer:

x = 30

Step-by-step explanation:

30 + 2x = 90

2x = 60

x = 30

8 0

3 years ago

The barrels weighed 834 pounds apiece. The ship's cargo included 618 barrels. Therefore, the barrels added pounds in weight to t

Mekhanik [1.2K]

I think you have to add the weights of the cargo ship

6 0

3 years ago

Give at least five (5) examples of statistical and non-statistical questions.

Anit [1.1K]

Answer (statistical):

1. How old are the students in this room?

2. What do 7th graders prefer to eat for lunch?

3. What time did the students in this class get up this morning?

4. What is the typical amount of pets owned by students in my class?

5. What were the high temperatures in all of the Latin American capitals today?

Answer (non-statistical):

1. What did Tom eat for lunch?

2. How old are you?

3. How many brothers does Marley have?

4. Did you get up on time today?

5. How many votes did the winning candidate for the Student Body receive this year?

7 0

3 years ago

If a point in the figure below is chosen at random, what is the probability that it is in the shaded region?​

If a point in the figure below is chosen at random, what is the probability that it is in the shaded region?