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kkurt [141]
3 years ago
12

In a multiple choice exam, there are 5 questions and 4 choices for each question (a, b, c, d). Nancy has not studied for the exa

m at all and decides to randomly guess the answers. What is the probability that: (a) the first question she gets right is the 5th question? (b) she gets all of the questions right? (c) she gets at least one question right?
Mathematics
1 answer:
Elina [12.6K]3 years ago
8 0

Answer: a) 0.07910, b) 0.000976, c) 0.7626

Step-by-step explanation:

Since we have given that

Number of questions = 5

Number of choices = 4

P(getting correct) = \dfrac{1}{4}=0.25

a) the first question she gets right is the 5th question?

P(getting 4 wrongs answers and one right answer) is given by

(1-0.25)^4\times 0.25\\\\=0.75^4\times 0.25\\\\=0.07910

b) she gets all of the questions right?

P(all right )= 0.25^5=0.000976

c) she gets at least one question right?

1-P(All of them wrong)

=1-(1-0.25)^5\\\\=1-0.7565\\\\=1-0.2373\\\\=0.7626

Hence, a) 0.07910, b) 0.000976, c) 0.7626

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I didn't get to finishing the problem (I just got distracted from my exams lol) but here are the equations for each of the people, if it helps.

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7 0
3 years ago
Given f(x)=x^2+5 and g(x)=2x^3-1 find (f/g)(-3)
AlekseyPX

For this case we have the following functions:

f (x) = x ^ 2 + 5\\g (x) = 2x ^ 3-1

By definition of composition of functions we have:

(f / g) (x) = \frac {f (x)} {g (x)}

Then substituting:

f (-3) = (- 3) ^ 2 + 5 = 9 + 5 = 14\\g (-3) = 2 (-3) ^ 3-1 = 2 (-27) -1 = -54-1 = -55

So:

(f / g) (- 3) = \frac {14} {- 55} = - 0.25

Answer:

(f / g) (- 3) = \frac {14} {- 55} = - 0.25

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3 years ago
Help !!! please show work so i know how to do it :)))
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Answer:

70

Step-by-step explanation:

the red lines mean the two sides are equal

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the inner angles of a triangle must add up to 180

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6 0
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The greatest common factor of 10 and 20 is 10.

4 0
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Answer:

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Step-by-step explanation:

3(7 + 4)2 − 24 ÷ 6 is the given expression.

Now, by the rule of BODMAS, where B = Bracket, O= of, D = divide,

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we try and solve the following expression in the same order.

Solving the bracket first, we get

3<u>(7 + 4)</u>2 − 24 ÷ 6 = 3(<u>11</u>)2 − 24 ÷ 6  =<u> 66</u>  − 24 ÷ 6

Next, we solve divide,

66 − <u>24 ÷ 6</u> = 66 - <u>4</u>  

Next, solving the subtraction, 66 - 4    = 62

Hence, 3(7 + 4)2 − 24 ÷ 6 = 62

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