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jus4u76
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01 Dec 2008, 9:08 pm

In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13



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01 Dec 2008, 9:18 pm

Deleted cos I'm stupid.


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Last edited by SeizeTheDay on 01 Dec 2008, 9:22 pm, edited 3 times in total.

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01 Dec 2008, 9:18 pm

jus4u76 wrote:
In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

70, because this number is the only one with both 5 and 7 as factors. (20% = 1/5).

jus4u76 wrote:
There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

1, because any combination of two sheep must have one that is white. If there were two or more black sheep, they would form at least one combination where neither of the sheep is white.

jus4u76 wrote:
Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

2012, because I used the "Adjust Date/Time" function of my toolbar clock to figure it out.

jus4u76 wrote:
You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13

9, because the first three balls could each be yellow, and the next 5 balls could each be red; thus, the next ball would have to be blue.

What did I win?



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01 Dec 2008, 9:20 pm

^^^^
What happens when the first 5 balls are red, then the next 4 are blue?

...so wouldn't it be 13??

What's with all of the IQ tests and questions? :?


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jus4u76
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01 Dec 2008, 9:25 pm

Fnord wrote:
jus4u76 wrote:
In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

70, because this number is the only one with both 5 and 7 as factors. (20% = 1/5).

jus4u76 wrote:
There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

1, because any combination of two sheep must have one that is white. If there were two or more black sheep, they would form at least one combination where neither of the sheep is white.

jus4u76 wrote:
Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

2012, because I used the "Adjust Date/Time" function of my toolbar clock to figure it out.

jus4u76 wrote:
You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13

9, because the first three balls could each be yellow, and the next 5 balls could each be red; thus, the next ball would have to be blue.

What did I win?


that's cheating 2012 and the answer is 13 balls.



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01 Dec 2008, 9:27 pm

1) 70. This is the only number evenly divisible by five and seven. (20%=1/5)

2) 1. If at least one out of any two sheep is white, then there can only be one black sheep. If there were 2 or more black sheep, one would have to entertain the posibility that both black sheep could be selected at the same time.

3) Not sure. I don't know when leap years are, off the top of my head.

4) 9. The only way to be sure that you have at least one ball of each color is control for the posibility that all of the balls of the red or yellow varieties are selected first. In such a situation, 5 reds and 3 blues are selected in the first eight tries. The nineth try will definitely yield a blue ball.



jus4u76
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01 Dec 2008, 9:27 pm

Kaysea wrote:
1) 70. This is the only number evenly divisible by five and seven. (20%=1/5)

2) 1. If at least one out of any two sheep is white, then there can only be one black sheep. If there were 2 or more black sheep, one would have to entertain the posibility that both black sheep could be selected at the same time.

3) Not sure. I don't know when leap years are, off the top of my head.

4) 9. The only way to be sure that you have at least one ball of each color is control for the posibility that all of the balls of the red or yellow varieties are selected first. In such a situation, 5 reds and 3 blues are selected in the first eight tries. The nineth try will definitely yield a blue ball.


im planning to major in math or computer science.



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01 Dec 2008, 9:28 pm

jus4u76 wrote:
Fnord wrote:
jus4u76 wrote:
In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

70, because this number is the only one with both 5 and 7 as factors. (20% = 1/5).

jus4u76 wrote:
There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

1, because any combination of two sheep must have one that is white. If there were two or more black sheep, they would form at least one combination where neither of the sheep is white.

jus4u76 wrote:
Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

2012, because I used the "Adjust Date/Time" function of my toolbar clock to figure it out.

jus4u76 wrote:
You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13

9, because the first three balls could each be yellow, and the next 5 balls could each be red; thus, the next ball would have to be blue.

What did I win?

that's cheating 2012 and the answer is 13 balls.

There is no cheating without pre-stated rules prohibiting the use of timekeeping devices.

Please demonstrate why "13" must be the correct answer.



Last edited by Fnord on 01 Dec 2008, 9:29 pm, edited 1 time in total.

jus4u76
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01 Dec 2008, 9:29 pm

Fnord wrote:
jus4u76 wrote:
Fnord wrote:
jus4u76 wrote:
In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

70, because this number is the only one with both 5 and 7 as factors. (20% = 1/5).

jus4u76 wrote:
There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

1, because any combination of two sheep must have one that is white. If there were two or more black sheep, they would form at least one combination where neither of the sheep is white.

jus4u76 wrote:
Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

2012, because I used the "Adjust Date/Time" function of my toolbar clock to figure it out.

jus4u76 wrote:
You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13

9, because the first three balls could each be yellow, and the next 5 balls could each be red; thus, the next ball would have to be blue.

What did I win?


that's cheating 2012 and the answer is 13 balls.


There is no cheating if there were no stated rules prohibiting the use of timekeeping devices.

Please demonstrate why "13" must be the correct answer.


it says so at the site. http://www.egopont.com/math/math_key.php



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01 Dec 2008, 9:29 pm

Kaysea wrote:

4) 9. The only way to be sure that you have at least one ball of each color is control for the posibility that all of the balls of the red or yellow varieties are selected first. In such a situation, 5 reds and 3 blues are selected in the first eight tries. The nineth try will definitely yield a blue ball.


What?! I don't understand that question... :x


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01 Dec 2008, 9:33 pm

Wouldn't it be 13 because if the first 5 were red and the next 4 were blue, you're screwed and you don't have any yellow...


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01 Dec 2008, 9:33 pm

jus4u76 wrote:
the answer is 13 balls.


Yeah, you are right. My logic was essentially correct, but I did it backwards.

Number 4 should state:
4) 9. The only way to be sure that you have at least one ball of each color is control for the posibility that all of the balls of the red or blue varieties (i.e. the two more common colours) are selected first. In such a situation, 5 reds and 7 blues are selected in the first twelve tries. If this were the case, the thirteenth try will definitely yield a yellow ball.



happypuff
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01 Dec 2008, 9:33 pm

For the date one:
in a leap year the same date will fall 2 days later
in a normal year the same date will fall 1 day later

So thursday 2007 = sat 2008 = sun 09 = mon 10 = tue 11 = thur 12



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01 Dec 2008, 9:34 pm

The website is wrong. Line up the balls in the following order, from left to right:

3 yellow balls, then 5 red balls, then the 7 blue balls (I did it with marbles, but the same principle applies).

Then you could see graphically that the minimum number of balls required to be picked is 9 IF you pick from left to right. You get the answer of 13 ONLY if you pick from right to left.

:P



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01 Dec 2008, 9:34 pm

Ugh... :wall:


I quit. :wall:


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01 Dec 2008, 9:43 pm

jus4u76 wrote:
Fnord wrote:
jus4u76 wrote:
Fnord wrote:
jus4u76 wrote:
In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

70, because this number is the only one with both 5 and 7 as factors. (20% = 1/5).

jus4u76 wrote:
There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

1, because any combination of two sheep must have one that is white. If there were two or more black sheep, they would form at least one combination where neither of the sheep is white.

jus4u76 wrote:
Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

2012, because I used the "Adjust Date/Time" function of my toolbar clock to figure it out.

jus4u76 wrote:
You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13

9, because the first three balls could each be yellow, and the next 5 balls could each be red; thus, the next ball would have to be blue.

What did I win?


that's cheating 2012 and the answer is 13 balls.

There is no cheating if there were no stated rules prohibiting the use of timekeeping devices.

Please demonstrate why "13" must be the correct answer.

it says so at the site. http://www.egopont.com/math/math_key.php

You did not include this link, or state the rules in your OP, so there was no reason for any following posters to assume that the use of timekeeping devices is prohibited. That's like saying that the first person to cross the finish line wins the race, and then waiting until after the race is won to tell the winner that he could not use his legs and feet.

:: I did not cheat.

jus4u76 wrote:
In Aunt Lucy's garden there are about 50-100 tulips. She says that 20% of the tulips are yellow and 1/7 of them are white. How many tulips does she have? ans: 80, 75, 70 or 56

There are exactly 100 sheep grazing in a field. Each of them is white or black. We know that among them there is at least one black sheep and out of any two at least one is white. How many black sheep are grazing in the field? 1,2,49 or 50

Baby Tom was born on Thursday, 24th of May, 2007. When will be his birthday on Thursday again? 2012,13,14 or 15

You have 5 red balls, 7 blue balls and 3 yellow balls in a box. You reach in without looking and pull out one ball at a time. What is the fewest number of balls you would need to take out to be sure you took out at least one ball of each color? 3,5,9 or 13