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Post by Dizzy D on Sept 29, 2016 10:33:35 GMT -5
So another mathical question:
Mom sends me out to buy animals. She gives me 100 bucks.
Chicks are $0.25
Pigs are $1
Cows are $40
She wants 100 animals in total, but she also wants all kinds of animals and no change.
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Post by Ish Kabbible on Sept 29, 2016 11:23:32 GMT -5
Ah, the chickens and rabbits I also was able to get so I'll show my workings x=number of rabbits
y= number of chickens
Assuming we don't have any headless chickens:
x+y=72
Assuming no crippled rabbits
4*x+2*y=200
x+y=72 so 2x+2y=144
4x+2y-2x-2y=200-144
2x=56
x=28
y=72-28=44
Another way to figure it with less formulas 72 heads equals 72 animals If they all had 2 feet that would be 144 feet. that leaves you 56 short of the required 200 So take the 56 you need and divide by 2 (the difference of a 4 legged animal vs 2 legs) and you get 28 rabbits that make up the difference you need 72 minus 28 gets you 44 chickens |
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Post by berkley on Sept 29, 2016 12:02:02 GMT -5
So another mathical question: Mom sends me out to buy animals. She gives me 100 bucks. Chicks are $0.25 Pigs are $1 Cows are $40 She wants 100 animals in total, but she also wants all kinds of animals and no change. I work this one out to: {Spoiler: Click to show}
52 chickens,
47 pigs, &
1 cow |
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Post by Dizzy D on Sept 29, 2016 12:56:58 GMT -5
That's correct.
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Post by berkley on Sept 29, 2016 19:07:38 GMT -5
Here's one that a friend of mine said he was once asked in a job interview (he works in IT):
Given a balance beam and 8 balls, with all except one being of the same weight, what is the minimum number of weighings it would take to find the odd one out? The balance beam doesn't give a measure, it just balances whatever is on one side with whatever is on the other.
edit: sorry, forgot to add that the odd one out is heavier than the other seven.
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Wild Card
Full Member
I'm out of my mind; But trapped inside my head!
Posts: 390 
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Post by Wild Card on Sept 30, 2016 2:25:29 GMT -5
Good question. I'm not meaning an offense to anyone, but how are we supposed to know that? I've never been good math, but I'm super confused. Maybe it's just baseball knowledge? It's a mathematical problem that I just worked out. I could have used many different numbers of at bats for any of them. But the key thing was to make sure Popeye's 2nd half at bats was much much higher than Bluto's first half at bats since between those two, Popeye had the higher batting average. Therefore I'm making the impact of Popeye's higher average huge when you total them all up It goes back to what I said was the moral of the story Oh. OH. So it's like those "find X" equations where X has multiple numbers that would make the equation work? |
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Post by Ish Kabbible on Sept 30, 2016 2:29:57 GMT -5
Here's one that a friend of mine said he was once asked in a job interview (he works in IT): Given a balance beam and 8 balls, with all except one being of the same weight, what is the minimum number of weighings it would take to find the odd one out? The balance beam doesn't give a measure, it just balances whatever is on one side with whatever is on the other. edit: sorry, forgot to add that the odd one out is heavier than the other seven. My only question would be does the person doing the weighing know in advance that the balls are equal weight with one exception? If so, wouldn't the answer be 1, if the first attempt shows they are not equal? If not known up front, would it be 3 attempts? First one is 4 balls on each side. Then take the heavier side and split them in two. Then repeat |
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Wild Card
Full Member
I'm out of my mind; But trapped inside my head!
Posts: 390
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Post by Wild Card on Sept 30, 2016 2:40:56 GMT -5
Here's one that a friend of mine said he was once asked in a job interview (he works in IT): Given a balance beam and 8 balls, with all except one being of the same weight, what is the minimum number of weighings it would take to find the odd one out? The balance beam doesn't give a measure, it just balances whatever is on one side with whatever is on the other. edit: sorry, forgot to add that the odd one out is heavier than the other seven. Wait wait wait, I got this one. Mostly due to excess time at work and no math involved. {Spoiler: Click to show}The answer is two! So. Let me see. Take two random balls and put them aside. Then take the six and out three on each side of the beam. If they don't balance out, then take the the three on the heavier side and weigh any two. If they balance out the ball you didn't weigh is heavier. If they don't, well the heavier one is, well...the heavier one. That's two. Oh, and if they do balance out, in the original weighing, then the heavier one is one of the left out ones. So weigh those and again, two weighs! |
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Post by Dizzy D on Sept 30, 2016 3:31:27 GMT -5
The balance beam/scales question was on Dara O'Briain's math show as well. It had a lot of neat little brainteasers like this.
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Post by Rob Allen on Sept 30, 2016 12:04:27 GMT -5
But we don't know if the "odd" ball is heavier or lighter than the other seven. You wouldn't know which side it's on without testing more.
Oops, just saw your edit. That does simplify the problem a lot.
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Post by Ish Kabbible on Oct 1, 2016 2:12:53 GMT -5
Sports Puzzle
Name the only man who had played for the New York Yankees baseball team, The New York Knicks basketball team and The New York Rangers hockey team
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Post by Prince Hal on Oct 1, 2016 9:51:34 GMT -5
Sports Puzzle Name the only man who had played for the New York Yankees baseball team, The New York Knicks basketball team and The New York Rangers hockey team Whoever was the organist. |
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Post by Ish Kabbible on Oct 1, 2016 13:39:34 GMT -5
Sports Puzzle Name the only man who had played for the New York Yankees baseball team, The New York Knicks basketball team and The New York Rangers hockey team Whoever was the organist. The Man Who Likes Suffering Dog Covers Is Correct  |
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Post by berkley on Oct 1, 2016 19:09:18 GMT -5
For the balance beam question, Ish's three weighings is as far as I know the standard answer and the one the job interviewers were looking for.
However, I have to admit that I have been unable to find a flaw in Yip Yip's answer and description - can anyone else see one?
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Post by Ish Kabbible on Oct 1, 2016 19:33:59 GMT -5
For the balance beam question, Ish's three weighings is as far as I know the standard answer and the one the job interviewers were looking for. However, I have to admit that I have been unable to find a flaw in Yip Yip's answer and description - can anyone else see one? The way I understand Yip Yip, if your not lucky, it's 3 weighs (if the heavier ball is one of the 2 you put aside in the beginning) |
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