I keep struggling on this question can someone help me figure it out

The circumference of F is 120 cm what is the length of DE the minor arc

AfilCa [17]

Answer:

Option E 15 cm

Step-by-step explanation:

we know that

The circumference of a circle subtends a central angle of 360 degrees

so

using proportion

Find out the length of arc DE by a central angle of 45 degrees

Let

x -----> the length of arc DE

$\frac{120}{360}=\frac{x}{45}\\\\x=120*45/360\\\\x=15\ cm$

7 0

3 years ago

Richard has just been given an l0-question multiple-choice quiz in his history class. Each question has five answers, of which o

myrzilka [38]

Answer:

a) 0.0000001024 probability that he will answer all questions correctly.

b) 0.1074 = 10.74% probability that he will answer all questions incorrectly

c) 0.8926 = 89.26% probability that he will answer at least one of the questions correctly.

d) 0.0328 = 3.28% probability that Richard will answer at least half the questions correctly

Step-by-step explanation:

For each question, there are only two possible outcomes. Either he answers it correctly, or he does not. The probability of answering a question correctly is independent of any other question. This means that we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

Each question has five answers, of which only one is correct

This means that the probability of correctly answering a question guessing is $p = \frac{1}{5} = 0.2$

10 questions.

This means that $n = 10$

A) What is the probability that he will answer all questions correctly?

This is $P(X = 10)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} = 0.0000001024$

0.0000001024 probability that he will answer all questions correctly.

B) What is the probability that he will answer all questions incorrectly?

None correctly, so $P(X = 0)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{10,0}.(0.2)^{0}.(0.8)^{10} = 0.1074$

0.1074 = 10.74% probability that he will answer all questions incorrectly

C) What is the probability that he will answer at least one of the questions correctly?

This is

$P(X \geq 1) = 1 - P(X = 0)$

Since $P(X = 0) = 0.1074$ , from item b.

$P(X \geq 1) = 1 - 0.1074 = 0.8926$

0.8926 = 89.26% probability that he will answer at least one of the questions correctly.

D) What is the probability that Richard will answer at least half the questions correctly?

This is

$P(X \geq 5) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 5) = C_{10,5}.(0.2)^{5}.(0.8)^{5} = 0.0264$

$P(X = 6) = C_{10,6}.(0.2)^{6}.(0.8)^{4} = 0.0055$

$P(X = 7) = C_{10,7}.(0.2)^{7}.(0.8)^{3} = 0.0008$

$P(X = 8) = C_{10,8}.(0.2)^{8}.(0.8)^{2} = 0.0001$

$P(X = 9) = C_{10,9}.(0.2)^{9}.(0.8)^{1} \approx 0$

$P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} \approx 0$

So

$P(X \geq 5) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10) = 0.0264 + 0.0055 + 0.0008 + 0.0001 + 0 + 0 = 0.0328$

0.0328 = 3.28% probability that Richard will answer at least half the questions correctly

8 0

3 years ago

The Length of a rectangle is 5 centimeters less than twice its width . The perimeter of the rectangle is 80cm. What are the dime

borishaifa [10]

Perimeter is the sum of all a shapes sides.

with that in mind, we know a rectangle has four sides. with 2 pairs being the same.

The length as told is, 5 centimeters less than two times the width. Two times the width would be 2w and five less than that would be minus five. so the length is 2w - 5

now to find the perimeter we do two times the width + two times the length.

2w + 2(2w -5) = 80.
Distribute: 2w + 4w - 10 = 80
Add ten to both sides and combine the 2w & 4w:
6w = 90
Divide both sides by 6: w = 15.

with this we know the width is 15. to find length plug in 15 to the 2w - 5 equation.

2(15) - 5 = 30 - 5 = 25.

Slap on the units and width = 15 cm, length = 25 cm

7 0

3 years ago

PLEASE HELP PLEASE HELP PLEASE

WARRIOR [948]

f is given as -3

-3 is greater than -4, so use the second equation 3x-5.

replace x with -3 and calculate:

3(-3) - 5 = -9 - 5 = -14

The answer is -14.

6 0

3 years ago

Sila jogged 12 kilometers today and wants to know how far she traveled in feet. What error did Sila make while converting from k

elena-14-01-66 [18.8K]

Answer:

sila put a wrong number in her calculator when multiplying the numerators

Step-by-step explanation:

Sila jogged 12 kilometers today and wants to know how far she traveled in feet. what error did sila make while converting from kilometers to feet?

StartFraction 12 kilometers Over 1 EndFraction times StartFraction 0.62 miles Over 1 kilometer EndFraction times StartFraction 5280 feet Over 1 mile EndFraction = 392,832 feet

sila put a wrong number in her calculator when multiplying the numerators.

1 km sila's first fraction should be 0 62 mi 1 mi

sila's last fraction should be 5280 ft

sila forgot to divide by 0 62 asap

(12kilometers / 1 ) × (0.62 miles / 1 kilometer) × 5280 / 1 mile

12 kilometers = 39,370.079 feet

1 kilometer = 0.621 miles

sila put a wrong number in her calculator when multiplying the numerators

4 0

3 years ago

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