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Alex73 [517]
3 years ago
7

A student takes a 20-question, multiple-choice exam with five choices for each question and guesses on each question. Find the p

robability of guessing at least 15 out of 20 correctly. Would you consider this event likely or unlikely to occur? Explain your answer.
Mathematics
1 answer:
Schach [20]3 years ago
6 0

Answer:

Step-by-step explanation:

Given that a student takes a 20-question, multiple-choice exam with five choices for each question and guesses on each question.

Since each question has 5 choices p = probability for success = pr for getting correct guess = 0.2

Each question is independent of the other and q= pr for failure =1-0.2=0.8

Hence we have X, no of correct questions in the test is binomial n =20 and p =0.2

the probability of guessing at least 15 out of 20 correctly

= P(x=15)\\=20C15 (0.2)^{15} (0.8)^5

<0.00001

So we can consider this event  unlikely to occur because the probability is almost zero.

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Consider the possible solution to each inequality. Choose Yes or No for each question.
ZanzabumX [31]

Answer:

a. No

b. Yes

c. No

d. Yes

e. Yes

Step-by-step explanation:

a. 8 + 13 = 21. No

b. -6 - 10 = -4. Yes

c. 6 × 4.6 = 27.6. No

d. 15 × 3.9 = 58.5. Yes

e. -6 × (-5) = 30. Yes

3 0
3 years ago
Solve this quadratic equation using the quadratic formula.<br> 5 - 10x - 3x2 = 0
Olegator [25]

-3x^2 - 10x + 5 = 0

Quadratic formula:

-b +/- sqrt[b^2 - 4(a)(c)]/2(a)

So. . . 10 +/- sqrt[(10^2) - 4(-3)(5)]/2(-3)

10 +/- sqrt[100+60]/ -6

10 +/- sqrt[160]/-6

5 0
3 years ago
Mr.Vance's yearly taxable income is $35,675.What is the dollar amount taken out for taxes based on Mr.Vance's taxable income?
Archy [21]
This is an incomplete problem. The missing information is 

Each bulleted statement describes how the amount of income tax is determined for yearly income in different ranges.

1) Yearly incomes of $8,925 or less are taxed at a flat rate of 10%.
2) For yearly incomes from $8,926 to $36,250, the first $8,925 is taxed at 10% and any income beyond $8,925 is taxed at 15%.
3) For yearly income greater than $36,250, the first $8,925 is taxed at 10%, the next $27,325 is taxed at 15%, and any income beyond $36,250 is taxed at 25%

The taxable income of Mr. Vance corresponds to number 2.

⇒ 8,925 * 10% = 892.50
⇒ 35,675 - 8,925 = 26,750 * 15% = 4,012.50

Total tax = 892.50 + 4,012.50 = 4,905
5 0
3 years ago
The perimeter of the rectangle she below is 24feet
maxonik [38]
This is really obvious but the answer is 4 feet.
6 0
3 years ago
After drawing the line y = 2x − 1 and marking the point A = (−2, 7), Kendall is trying to decide which point on the line is clos
igor_vitrenko [27]

Answer:

Step-by-step explanation:

Having drawn the line, Kendall must verify that the point P belongs to the line y = 2x-1 and then calculate the distance between A-P  and verify if it is the closest to A or there is another one of the line

Having the point P(3,5) substitue x to verify y

y=2*(3)-1=6-1=5 (3,5)

Now if the angle formed by A and P is 90º it means that it is the closest point, otherwise that point must be found

d_{AP}=\sqrt{(y_{2}-y_{1})^{2}+(x_{2}-x_{1})^{2}}=\sqrt{(5-7)^{2}+(3-(-2}))^{2}}=\\\sqrt{(-2)^{2}+(5)^{2}}=\sqrt{29}

and we found the distance PQ and QA

; d_{PQ}=\sqrt{125}, d_{QA}=12

be the APQ triangle we must find <APQ through the cosine law (graph 2).

3 0
3 years ago
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