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2 years ago

15

A teacher gave students seven questions and wrote that she would randomly choose one of the seven questions for an exam. If harr

y prepared for only one of the questions, what is the probability that he did not study for the question that the teacher put on the exam?

1 answer:

VashaNatasha [74]2 years ago

6 0

Answer:

I thinks its

$\frac{6}{7}$

But i can be wrong

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According to a 2013 study by the Pew Research Center, 15% of adults in the United States do not use the Internet (Pew Research C

Pavel [41]

Answer:

a) For this case we can use the binomial model since we assume independent events and the same probability for each trial is the same p =0.15

b) $P(X=0)=(10C0)(0.15)^0 (1-0.15)^{10-0}=0.1969$

c) $P(X=3)=(10C3)(0.15)^3 (1-0.15)^{10-3}=0.1298$

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

And using the result from part a we got:

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

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n p)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

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

Solution to the problem

Part a

For this case we can use the binomial model since we assume independent events and the same probability for each trial is the same p =0.15

Part b

For this case we want this probability:

$P(X=0)$

And replacing we got:

$P(X=0)=(10C0)(0.15)^0 (1-0.15)^{10-0}=0.1969$

Part c

For this case we want this probability:

$P(X=3)$

And replacing we got:

$P(X=3)=(10C3)(0.15)^3 (1-0.15)^{10-3}=0.1298$

Part d

For this cae we want thi probability:

$P(X \geq 1)$

And we can use the complment rule and we got:

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

And using the result from part a we got:

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

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2 years ago

On a coordinate plane, a triangle has points A prime (negative 2, 10), B prime (negative 6, 4), and (negative 10, 8). What is th

schepotkina [342]

Answer:

A(10,-2).

Step-by-step explanation:

It is given that, on a coordinate plane, a triangle has points A'(-2, 10), B'(-6, 4), and C'(-10, 8).

We need to find the pre-image of vertex A' if the image shown on the graph was created by a reflection across the line y = x.

If a figure reflected across the line y=x, then

$A(x,y)\rightarrow A'(y,x)$

It is given that A'(-2,10).

$A(y,x)=A'(-2,10)$

On comparing both sides, we get

$x=10,y=-2$

Therefore, the coordinates of preimage of A' are (10,-2).

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2 years ago

Find the value of x RT=4x+10 SW= 5x-20

Liula [17]

Well, as you can see from the rectangle RT and SW should have equal lengths. So to find the value of x, we need to do.....

4x + 10 = 5x - 20
-x + 10 = -20 (Subtraction property of equality)
-x = -30 (Subtraction property of equality)
x = 30 (Division property of equality)

To check our work:

4(30)+10 = 130
5(30)-20 = 130

So, the value of x is 30!

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