The difference of nine times a number and the quotient of 6 and the same number.

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

HELP PLEASE!!!!!!!!

eimsori [14]

Answer:

8) B. 70

9)C. 6 1/4

10) D. 2,000

hope this helped

3 0

3 years ago

When completely factored, x^2 + x - 6 is equivalent to which of the following? A. (x + 1)(x – 6) B. (x + 3)(x – 2) C. (x + 6)(x

Mariana [72]

X^2+x-6

x^2-2x+3x-6

x(x-2)+3(x-2)

(x+3)(x-2)

5 0

3 years ago

-5x-12>6x-4 Solve the inequality and give the answer in interval notation.

lora16 [44]

-5x-12>6x-4

To Solve the inequality we need to get x alone

-5x-12>6x-4

first we remove -12, for that we add 12 on both sides

-5x-12+12>6x-4+12

-5x > 6x +8

Now subtract 6x from both sides

-5x -6x> 6x-6x +8

-11x > 8

Divide by -11. when we divide by -11 we flip the inequality . so > becomes <

$x < -\frac{8}{11}$

We need to give the answer in interval notation.

x is less than -8/11 so x value starts from -8/1 and goes to -infinity(left)

So interval notation is (-∞, $-\frac{8}{11}$ )

7 0

3 years ago

Consider a Triangle ABC like the one below. Suppose that C = 98, A = 74, and b = 11 (figure is not drawn to scale.) solve the tr

Degger [83]

Answer:

$A=73.8\°$

$B=8.2\°$

$c=76.3\ units$

Step-by-step explanation:

step 1

Find the measure of side c

Applying the law of cosines

$c^{2}= a^{2}+b^{2}-2(a)(b)cos(C)$

substitute the given values

$c^{2}= 74^{2}+11^{2}-2(74)(11)cos(98\°)$

$c^{2}=5,823.5738$

$c=76.3\ units$

step 2

Find the measure of angle A

Applying the law of sine

$\frac{a}{sin(A)}=\frac{c}{sin(C)}$

substitute the given values

$\frac{74}{sin(A)}=\frac{76.3}{sin(98\°)}$

$sin(A)=(74)sin(98\°)/76.3$

$A=arcsin((74)sin(98\°)/76.3)$

$A=73.8\°$

step 3

Find the measure of angle B

we know that

The sum of the internal angles of a triangle must be equal to 180 degrees

so

$A+B+C=180\°$

substitute the given values

$73.8\°+B+98\°=180\°$

$171.8\°+B=180\°$

$B=180\°-171.8\°=8.2\°$

5 0

3 years ago

The difference of nine times a number and the quotient of 6 and the same number.​

The difference of nine times a number and the quotient of 6 and the same number.