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3 years ago

HELP RIGHT AWAY IF YOU SEE

Mathematics

1 answer:

fenix001 [56]3 years ago

7 0

Answer:

I would say A

Step-by-step explanation:

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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

A pillow that usually costs $20 is marked down 45%. Table Use the table to find the new price of the pillow. $9 $11 $29 $33

sattari [20]

It would now cost $11. 45% of 20 is 9, therefore, you would subtract 9 from 20 (since it is getting marked down).

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A basketball is shot into a 10ft. Goal from a height of 6.5 feet. The function h= -0.875t2 + 3.5t + 6.5 represents the path of t

Galina-37 [17]

Answer: how do I graph this

Step-by-step explanation:

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3 years ago

The mean of four consecutive even numbers is 15. The greatest of these numbers is a1. The least of these numbers is a2.

skad [1K]

X + (x + 2) + ( x + 4) + (x + 6)
-----------------------------------   = 15
   4

4x + 12
--------- = 15
    4

Multiply by 4 on both sides

4x + 12 = 60
subtract 12 from both sides
4x = 48
divide by 4 on each side
x = 12
x + 2 = 14
x + 4 = 16
x + 6 = 18

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3 years ago

What is 15/27 in a decimal?

amid [387]

Answer:

0.55555

Step-by-step explanation:

the 5 keeps repeating

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