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3 years ago

7

Can someone help me! Thanks :)

1 answer:

Citrus2011 [14]3 years ago

7 0

The answer is B -2a :)

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A multiple-choice examination has 15 questions, each with five answers, only one of which is correct. Suppose that one of the st

Alex

Answer:

0.0111% probability that he answers at least 10 questions correctly

Step-by-step explanation:

For each question, there are only two outcomes. Either it is answered correctly, or it is not. The probability of a question being answered correctly is independent from other questions. So 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.

A multiple-choice examination has 15 questions, each with five answers, only one of which is correct.

This means that $n = 15, p = \frac{1}{5} = 0.2$

What is the probability that he answers at least 10 questions correctly?

$P(X \geq 10) = P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) + P(X = 15)$

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

$P(X = 10) = C_{15,10}.(0.2)^{10}.(0.8)^{5} = 0.0001$

$P(X = 11) = C_{15,11}.(0.2)^{11}.(0.8)^{4} = 0.000011$

$P(X = 12) = C_{15,12}.(0.2)^{12}.(0.8)^{3} \cong 0$

$P(X = 13) = C_{15,13}.(0.2)^{13}.(0.8)^{2} \cong 0$

$P(X = 14) = C_{15,14}.(0.2)^{14}.(0.8)^{1} \cong 0$

$P(X = 15) = C_{15,15}.(0.2)^{15}.(0.8)^{0} \cong 0$

$P(X \geq 10) = P(X = 10) + P(X = 11) + P(X = 12) + P(X = 13) + P(X = 14) + P(X = 15) = 0.0001 + 0.000011 = 0.000111$

0.0111% probability that he answers at least 10 questions correctly

3 0

3 years ago

MARK BRAINLIEST AND 12 POINTS

attashe74 [19]

Answer:

17

125

Step-by-step explanation:

exterior angle is equal to sum of interior opposite angle. so

( 2x + 6 ) + ( 5x ) = ( 8x - 11 )

7x + 6 = 8x - 11

x = 17

exterior angle = ( 8 * 17 ) - 11 = 125

8 0

3 years ago

Read 2 more answers

A car takes 4 hours to cover a certain distance, travelling at a speed of 120 km/h. How long will the car take if it travels at

muminat

Answer:

3/8 hours

Step-by-step explanation:

distance=speed/time=120/4=30km

time=distance/speed=30/80=3/8

4 0

3 years ago

Read 2 more answers

Beyonce and Guns N Roses had the two top-grossing North American concert tours for 2016, together generating $300 million in tic

ipn [44]

Answer:

Step-by-step explanation:

B + G = 300 (million)

G = B - 38 (million)

B + B - 38 = 300

2B - 38 = 300

2B = 300 + 38

2B = 338

B = 338/2

B = 169 million <=== Beyonce

G = B - 38

G = 169 - 38

G = 131 million <==== Guns N Roses

5 0

3 years ago

Please help do not answer if u don't know it

AveGali [126]

Answer:

the answer is D

Step-by-step explanation:

3 0

3 years ago