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math & puzzles Online Quiz - 36

Description: math & puzzles Online Quiz - 36
Number of Questions: 20
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Tags: math & puzzles
Attempted 0/20 Correct 0 Score 0

Someone shows you two boxes and he tells you that one of these boxes contains two times as much as the other one, but he does not tell you which one this is. He lets you choose one of these boxes, and opens it. It turns out to be filled with \$10. Now he gives you the opportunity to choose the other box instead of the current one (and skip the \$10 of the first box), because the second box could contain twice as much (i.e. \$20). The Question: Should you choose the second box, or should you stick to your first choice to maximize the expected amount of money? A Hint : If you have \$10, and you could double this with a chance of 1/2, or half it with a chance of 1/2, one would expect an average of 1/2 * \$20 + 1/2 * \$5 = \$12.5 (so you would expect to gain $2.5)!...

  1. Take the first box

  2. Take the second box

  3. Doesn't make difference

  4. Indeterminable


Correct Option: A

AI Explanation

To answer this question, we need to consider the probabilities and expected values associated with each choice.

Let's go through each option to understand why it is correct or incorrect:

Option A) Take the first box - This option is correct. If we choose the first box, we are guaranteed to receive \$10. The probability of the other box containing double this amount is uncertain, so it is safer to stick with the known amount of \$10. The expected value of this choice is \$10.

Option B) Take the second box - This option is incorrect. While there is a possibility that the second box contains double the amount of the first box (\$20), there is also a possibility that it contains half the amount (\$5). The expected value of this choice would be the average of these possibilities, which is \$12.5. However, it is important to note that the expected value does not guarantee the actual outcome.

Option C) Doesn't make a difference - This option is incorrect. The choice between the two boxes does make a difference because the first box already guarantees \$10, while the second box has uncertain outcomes.

Option D) Indeterminable - This option is incorrect. The choice can be determined based on the probabilities and expected values associated with each option.

The correct answer is Option A) Take the first box. This option is correct because it guarantees \$10, while the second box has uncertain outcomes.

In a city called Veldhoven the following facts are true: No two inhabitants have exactly the same number of hairs. No inhabitant has exactly 40360 hairs. There are more inhabitants than there are hairs on the head of any one inhabitant. What is the largest possible number of inhabitants of Veldhoven (knowing that the number of inhabitants is not infinite)?

  1. 0

  2. 40359

  3. 40360

  4. 40361


Correct Option: C

Three men (Tom, Peter and Jack) and three women (Eliza, Anne and Karen) are spending a few months at a hillside. They are to stay in a row of nine cottages, each one living in his or her own cottage. There are no others staying in the same row of houses.

A.Anne, Tom and Jack do not want to stay in any cottage, which is at the end of the row.
B.Eliza and Anne are unwilling to stay besides any occupied cottage..
C.Karen is next to Peter and Jack.
D.Between Anne and Jackâs cottage there is just one vacant house.
E.None of the girls occupy adjacent cottages.
F.The house occupied by Tom is next to an end cottage.

Which of the above statements can be said to have been derived from two other statements ?

  1. A

  2. B

  3. C

  4. E


Correct Option: D

AI Explanation

To solve this question, we need to analyze each statement and determine which statements can be derived from two other statements. Let's go through each statement:

A. Anne, Tom, and Jack do not want to stay in any cottage, which is at the end of the row. B. Eliza and Anne are unwilling to stay beside any occupied cottage. C. Karen is next to Peter and Jack. D. Between Anne and Jack's cottage, there is just one vacant house. E. None of the girls occupy adjacent cottages. F. The house occupied by Tom is next to an end cottage.

We can try to derive each statement using the other statements:

A cannot be derived using the other statements because it is a unique condition mentioned in the problem statement.

B cannot be derived using the other statements because it is also a unique condition mentioned in the problem statement.

C cannot be derived using the other statements because it is also a unique condition mentioned in the problem statement.

D can be derived using statements C and E. If Karen is next to Peter and Jack, and none of the girls occupy adjacent cottages, then there must be exactly one vacant house between Anne and Jack's cottage.

E cannot be derived using the other statements because it is a unique condition mentioned in the problem statement.

F cannot be derived using the other statements because it is a unique condition mentioned in the problem statement.

Therefore, the statement that can be said to have been derived from two other statements is D.

Three men (Tom, Peter and Jack) and three women (Eliza, Anne and Karen) are spending a few months at a hillside. They are to stay in a row of nine cottages, each one living in his or her own cottage. There are no others staying in the same row of houses. Anne, Tom and Jack do not want to stay in any cottage, which is at the end of the row. Eliza and Anne are unwilling to stay besides any occupied cottage.. Karen is next to Peter and Jack. Between Anne and Jack’s cottage there is just one vacant house. None of the girls occupy adjacent cottages. The house occupied by Tom is next to an end cottage. How many of them occupy cottages next to a vacant cottage ?

  1. 2

  2. 3

  3. 4

  4. 6


Correct Option: C

AI Explanation

To solve this question, we need to follow the given conditions and determine the number of people who occupy cottages next to a vacant cottage.

Let's analyze each condition:

  1. Anne, Tom, and Jack do not want to stay in any cottage which is at the end of the row.

This means that Anne, Tom, and Jack cannot occupy the first or last cottage in the row.

  1. Eliza and Anne are unwilling to stay beside any occupied cottage.

This means that Eliza and Anne cannot occupy cottages next to any occupied cottage.

  1. Karen is next to Peter and Jack.

This implies that Karen must be occupying a cottage between Peter and Jack.

  1. Between Anne and Jack's cottage, there is just one vacant house.

This means that there is only one empty cottage between Anne and Jack.

  1. None of the girls occupy adjacent cottages.

This condition implies that the girls (Eliza, Anne, and Karen) cannot occupy adjacent cottages.

  1. The house occupied by Tom is next to an end cottage.

This means that Tom must be occupying a cottage next to either the first or last cottage.

Now let's arrange the cottages and determine the occupants:


Considering condition 1, we can eliminate the first and last cottage:


Considering condition 4, we can place Anne and Jack in two consecutive cottages with one vacant cottage between them:

_ _ A J _ _ _ _

Considering condition 5, we know that none of the girls can occupy adjacent cottages, so Eliza cannot be placed in the two vacant cottages next to Anne and Jack. Therefore, Eliza must be placed in one of the outer cottages:

E _ A J _ _ _ _

Considering condition 6, Tom must be placed in one of the two outer cottages:

E _ A J _ _ _ T

Considering condition 2, Eliza cannot be placed in the cottage next to an occupied cottage, so she must be placed in the remaining outer cottage:

E _ A J _ _ K T

Considering condition 3, Karen must be placed between Peter and Jack, so she must be placed in the cottage next to Jack:

E _ A J K _ _

Now we have one vacant cottage left. According to condition 5, none of the girls can occupy this cottage, so Peter must be placed in this cottage:

E _ A J K P _

Therefore, the final arrangement is:

E P A J K P T

From the arrangement, we can see that there are 4 people (Eliza, Anne, Jack, and Karen) who occupy cottages next to a vacant cottage.

Therefore, the correct answer is C) 4.

Given the mathematical set N of natural numbers (0, 1, 2, 3, 4, 5, ...) and the set Z of integer numbers (..., -3, -2, -1, 0, 1, 2, 3, 4, ...). Which of the following sentences is true?

  1. N has less numbers than Z

  2. N has as many numbers as Z

  3. N has more numbers than Z

  4. Indeterminable


Correct Option: B

Three men (Tom, Peter and Jack) and three women (Eliza, Anne and Karen) are spending a few months at a hillside. They are to stay in a row of nine cottages, each one living in his or her own cottage. There are no others staying in the same row of houses. Anne, Tom and Jack do not want to stay in any cottage, which is at the end of the row. Eliza and Anne are unwilling to stay besides any occupied cottage.. Karen is next to Peter and Jack. Between Anne and Jack’s cottage there is just one vacant house. None of the girls occupy adjacent cottages. The house occupied by Tom is next to an end cottage. Which among these statement(s) are true ? 1. Anne is between Eliza and Jack. 2. At the most four persons can have occupied cottages on either side of them. . 3. Tom stays besides Peter

  1. 1 OLY

  2. 2 OLY

  3. 1 AND 3 OLY

  4. 1, 2 AND 3


Correct Option: C

AI Explanation

To solve this question, let's go through each statement and determine if it is true or false.

Statement 1: Anne is between Eliza and Jack. This statement is true. From the given information, we know that Karen is next to Peter and Jack. Since Anne, Tom, and Jack do not want to stay in any cottage at the end of the row, it means that Eliza must be at one end of the row, and Jack must be at the other end. Therefore, Anne must be between Eliza and Jack.

Statement 2: At most four persons can have occupied cottages on either side of them. This statement is false. If Tom stays next to an end cottage and Anne, Tom, and Jack do not want to stay in any cottage at the end of the row, it means that Tom cannot have more than one person on his side. Therefore, at most three persons can have occupied cottages on either side of Tom.

Statement 3: Tom stays besides Peter. This statement is true. From the given information, we know that Karen is next to Peter and Jack. Since Tom stays next to an end cottage, it means that Tom can only be next to Peter.

Based on our analysis, the correct statements are 1 and 3. Therefore, the correct answer is option C: 1 and 3 only.

204, 527, 386, 112, 734 What are the next two numbers in this sequence...

  1. 750 AND 138

  2. 799 AND 131

  3. 745 AND 999

  4. 799 AND 880


Correct Option: C

You have three bags, each containing two marbles. Bag A contains two white marbles, Bag B contains two black marbles, and Bag C contains one white marble and one black marble. You pick a random bag and take out one marble. It is a white marble. What is the probability that the remaining marble from the same bag is also white?

  1. 2/3

  2. 1/2

  3. 2/4

  4. 4/7


Correct Option: A

If 2x-y=4 then 6x-3y=?

  1. 15

  2. 12

  3. 18

  4. 20


Correct Option: B

If x=y=2z and xyz=256 then what is the value of x?

  1. 12

  2. 16

  3. 8

  4. 6


Correct Option: C

(1/10)18 - (1/10)20 = ?

  1. 99/1020

  2. 0.99

  3. 99/10

  4. none of these


Correct Option: A

Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time

  1. 20 1/7 mins

  2. 8 mins

  3. 17 1/7 mins

  4. none


Correct Option: C

Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?

  1. 8

  2. 7 1/2

  3. 7

  4. 9


Correct Option: B

It is a 5 digit number.If we put the numeral 1 at the beginning, we get a number three times smaller than if we put the numeral 1 at the end of the number

  1. 37648

  2. 21734

  3. 42857

  4. 74329


Correct Option: C

2,6,12,20,xValue of x?

  1. 24

  2. 25

  3. 28

  4. 30

  5. 36

  6. 40


Correct Option: D

Using the digits 1 up to 9, two numbers must be made. The product of these two numbers should be as large as possible. All digits must be used exactly once. The Question: Which are the requested two numbers?

  1. 9642, 87531

  2. 9753, 86421

  3. 98756, 4321

  4. 97531, 8642


Correct Option: A

AI Explanation

To maximize the product of two numbers formed using the digits 1 to 9, we need to consider the place value of each digit.

Let's analyze each option:

A. 9642, 87531 The larger number, 87531, is formed by placing the larger digits in the higher place values. This arrangement maximizes the product.

B. 9753, 86421 In this option, the larger number, 86421, has a smaller digit, 6, in the highest place value compared to option A. Therefore, the product will be smaller than option A.

C. 98756, 4321 The larger number, 98756, is formed by placing the larger digits in the higher place values. However, the smaller number, 4321, has the smaller digits in the higher place values compared to option A. Therefore, the product will be smaller than option A.

D. 97531, 8642 In this option, the larger number, 97531, is formed by placing the larger digits in the higher place values. However, the smaller number, 8642, has a smaller digit, 6, in the highest place value compared to option A. Therefore, the product will be smaller than option A.

Therefore, the correct answer is A, where the two numbers are 9642 and 87531.

Three friends Pablo, Edvard, and Henri are talking to each other about the art collection of Leonardo. Pablo says: "Leonardo has at least four paintings of Rembrandt." Edvard says: "No, he has less than four paintings of Rembrandt." "According me," says Henri, "Leonardo has at least one Rembrandt." The Question: If you known that only one of the three friends is right, how many Rembrandts does Leonardo possess?

  1. 0

  2. 1/2/3

  3. 4

  4. > 4


Correct Option: A

Richard is a strange liar. He lies on six days of the week, but on the seventh day he always tells the truth. He made the following statements on three successive days: Day 1: "I lie on Monday and Tuesday." Day 2: "Today, it's Thursday, Saturday, or Sunday." Day 3: "I lie on Wednesday and Friday." The Question: On which day does Richard tell the truth?

  1. Sunday

  2. Monday

  3. Friday

  4. Tuesday

  5. Thursday


Correct Option: D

AI Explanation

To answer this question, let's analyze each statement made by Richard on three successive days:

Day 1: "I lie on Monday and Tuesday." This statement means that Richard is lying on Monday and Tuesday. Since Richard lies on six days of the week, this statement is consistent with his lying behavior.

Day 2: "Today, it's Thursday, Saturday, or Sunday." This statement is a bit tricky. If Richard is telling the truth, then it must be either Thursday, Saturday, or Sunday. However, since Richard only tells the truth on the seventh day, this statement is inconsistent with his lying behavior. Therefore, Richard is lying on Day 2.

Day 3: "I lie on Wednesday and Friday." This statement means that Richard is lying on Wednesday and Friday. Since Richard lies on six days of the week, this statement is consistent with his lying behavior.

Based on the statements made by Richard, we can conclude that Richard tells the truth on the day after the second lie. Since Richard lied on Day 2, the day after the second lie is Day 3. Therefore, Richard tells the truth on Tuesday.

The correct answer is D) Tuesday.

On an early morning, three rivals get together on an open spot in a dark wood to compose a quarrel by means of guns. A kind of duel, but with three persons: A, B and C. The rules of the game are: They draw lots who may fire first, second and third. Next, they will continue firing at each other in this order until only a single person is alive. Every person decides himself at which person he fires. Everyone knows that A hits (kills) in 100% of all shots, B hits (kills) in 80% of all shots and C hits (kills) in 50% of all shots. Each person chooses his ideal strategy. No one is killed by a stray bullet. The Question: Who has the largest chance of surviving the truel, and how big is this chance?

  1. A, > 80%

  2. B, > 50%

  3. C, > 50%

  4. A, > 50%

  5. B, > 30%


Correct Option: C

A does a work in 15 hrs .B is 60% more efficient than a .how much time will B take to complete the work?

  1. 12

  2. 9

  3. 6

  4. 10


Correct Option: C
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