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        riddles >> easy >> Delta Airlines Riddle
        
(Message started by: SWF on Jan 7^th, 2012, 10:14am)

Title: Delta Airlines Riddle
Post by SWF on Jan 7^th, 2012, 10:14am

This question is in this month's "Sky" magazine, which can be found in seat backs if you fly on Delta airlines:

A farmer has a 100 foot by 200 foot rectangular plot of land. If he divides that into as many square 900 square foot plots of land as possible, how many square feet of land are left unused?

Title: Re: Delta Airlines Riddle
Post by towr on Jan 7^th, 2012, 11:16am

[hide]Probably much less than 3800, I expect you can squeeze in a few extra squares when you put them all at an angle, rather than parallel to the sides of the rectangle. I'll guess 1100.[/hide]

Title: Re: Delta Airlines Riddle
Post by playful on Jan 7^th, 2012, 1:58pm

I'm going to stick with 1800.
When I mentally try to slide the yellow squares inside the white box, I don't see another square magically appearing.
Okay, my squares are not quite square. :)

http://img831.imageshack.us/img831/1214/squares.png

Title: Re: Delta Airlines Riddle
Post by towr on Jan 7^th, 2012, 2:54pm

[hide]Maybe it's a trick question..
Do the square plots have to be completely filled?[/hide]

Title: Re: Delta Airlines Riddle
Post by rmsgrey on Jan 7^th, 2012, 7:00pm

Given the source, I'd say that the intended answer is for a 3*6 grid to be used, with the remainder unused.

Some quick (and possibly unreliable) mental calculations suggest you can't fit a 7*1 strip along the diagonal (the diagonal is more than 7 plots long, but less than the 7.8 my calculations suggest is required to allow the width of the strip to fit)

Title: Re: Delta Airlines Riddle
Post by SWF on Jan 7^th, 2012, 7:36pm

Given the source, and the fact that this was question #1 of a set of easy questions, I was also expecting the answer to be what is left after removing the 3 by 6. However that is not the answer that was given, and that is the reason I posted it here. The only answer given was a number in square feet (not a picture). By the way, I don't agree with the answer given in the magazine.

Title: Re: Delta Airlines Riddle
Post by towr on Jan 8^th, 2012, 6:50am

I get [hide] 200 [/hide] square feet left over.
See the attachment for the configuration of plots.

Title: Re: Delta Airlines Riddle
Post by SWF on Jan 8^th, 2012, 1:20pm

I like that answer towr! The number you give even matches the answer given in the magazine, although I doubt that is what they were thinking.

Title: Re: Delta Airlines Riddle
Post by rmsgrey on Jan 9^th, 2012, 7:01am

So the magazine either assumed that the shape constraint didn't matter, or just didn't realise that they were only finding a lower bound rather than an exact answer...

Title: Re: Delta Airlines Riddle
Post by SWF on Jan 11^th, 2012, 9:45pm

Based on the simplicity of the other question, the magazine's intent was probably to solve by finding remainder when 100x200 is divided by 900 and taking the remainder. But they mistakenly turned it into a good question by specifying that the plots be square.

Title: Re: Delta Airlines Riddle
Post by chrs1 on Feb 4^th, 2012, 1:30pm

200 sq feet