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2tankhamun Newbie
Joined: 13 May 2010 Posts: 1

Posted: Thu May 13, 2010 1:11 am Post subject: DOING THE MATH RE: HOME PAGE MINDBENDERS OF AREA51 


I searched the forums for the word "math" and didn't find any posts concerning Allysa's "Mindbenders" on the home page of this site. Please pardon if these were addressed somewhere...
Three guys go out to dinner, each pays $10. The meals were discounted, waitress returns with $5. Applying the math correctly to the situation at hand: The total cost of the meals after discount was ($30  $5 = $25). So each guy's meal actual cost is $25 divided by 3 = $8.33 and 1/3 cents. Each guy contributed $10, so each guy should get back in change: ($10  $8.33 and 1/3 cents) = $1.66 and 2/3 cents. But each guy only got back $1. The amount each guy did not get back, 66 and 2/3 cents, went to the waitress. 3 guys x 66 and 2/3 cents = $2. The amount the waitress kept. All $$ has been accounted for.
As to the employment vacation mindbender, the premise that the time you are away from work can be totalled as cumulative days is a false premise. A work day is not the same as a calendar day. The hours and minutes a day you aren't working should removed from the same calendar day. 24 hours a day  16 hours away  1 hour at lunch  1/2 hour on break = 6.5 actual work hours per 24 hour day. (We call this "Banker's Hours" in the USA) Using the figures you provide: Number of days a year that you work = 261  14 vacation  5 holiday 2 sick = 240 calendar days per year that you report for work. 240 days x 6.5 hours worked each day = 1,560 hours worked per year. 365 days per year x 24 hours per day = 8,760 hours in a year. Number of hours a year you don't work = 8760  1560 = 7,200 hours. If you want to think of these two figures as consecutive days: Number of 24 hour days your work hours would amount to if they occured consecutively: 1,560 divided by 24 = 65. Number of 24 hour days your off time would amount to if they occured consecutively: 7,200 divided by 24 = 300. 300 calendar days off + 65 calendar days working = 365 calendar days in a year. If this seems offbalance to you, just remember, the for the 240 calendar days a year you report to work, you actually only work 6.5 hours of each of those days. The other 17.5 hours of each of those 240 calendar days PLUS all 24 hours of the 124 calendar days you don't report to work total the number of hours a year you don't work. And by the way, there are 52.143 weeks in a year, not 52. 52 weeks x 7 days per week = 364 days. 

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Lamiaceae Site Administrator
Joined: 05 Jul 2006 Posts: 7651 Location: To the right of my computer

Posted: Fri May 14, 2010 11:21 am Post subject: 


Take it you mean from here
http://www.area51newmexico.com/mind.php
Quote: 
Three guys go out to dinner, each pays $10. The meals were discounted, waitress returns with $5. Applying the math correctly to the situation at hand: The total cost of the meals after discount was ($30  $5 = $25). So each guy's meal actual cost is $25 divided by 3 = $8.33 and 1/3 cents. Each guy contributed $10, so each guy should get back in change: ($10  $8.33 and 1/3 cents) = $1.66 and 2/3 cents. But each guy only got back $1. The amount each guy did not get back, 66 and 2/3 cents, went to the waitress. 3 guys x 66 and 2/3 cents = $2. The amount the waitress kept. All $$ has been accounted for.

That's what's happening, but how do you give someone 1/3 of a cent?
Because you can't, it's 'lost'. It's all to do with rounding numbers off.
I argued this with my maths teacher during some trial important maths test ( so I was perhaps about 14 as a guess ).
The question had a lift/elevator which was a certain size, and you had to work out how many people would fit in it.
My workings out ( which I showed in full ) came to 3.3 people. Stupid, I said to myself, you can't have .3 of a person, therefore this lift can carry 3 people.
I was marked wrong, because I had said sorry, you can't get in this lift to .3 of a person.
No matter how much I argued, he was adamant that my answer was wrong. I answered the question correctly, 'how many people can fit in this lift' the answer was 3 because you can't have .3 of a person.
Speaking of which there's a thread I can make from that webpage, will be back later tonight. _________________ I should update my sig. What to put here for $CurrentYear ? 

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