Todays Brain Teaser #33 (09JUL2013)

[vpnavy]

Today's Brain Teaser #33 (09JUL2013)

A steer weighing 630 kilograms requires 13,500 calories a day to maintain its weight. That amount of food turns out to be proportional to its external surface.

How many calories does a steer of 420 kilograms require?

 

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[GMD52]

9000 calories

 

[Crispin]

13500

 

[Uncle Jeff]

Grrr VPNavy makin me due math and hurt my brain ...

10,300 calories

 

[vpnavy]

A steer weighing 630 kilograms requires 13,500 calories a day to maintain its weight. That amount of food turns out to be proportional to its external surface.

How many calories does a steer of 420 kilograms require?

Grrr VPNavy makin me due math and hurt my brain ...10,300 calories

Correct!

Weight is proportional to linear dimension (length or girth of the steer) cubed. Surface area is proportional to linear dimension squared. Therefore - 13,500 x [ (420/630)1/3 ] 2 = 10,300 calories!

Stay tuned for tomorrow's!
==============================
BRAIN TEASER WINNERS
==================
(33 - Jul 09, 2013) Uncle Jeff (3)
(32 - Jul 08, 2013) Red James cash (3)
(31 - Jul 07, 2013) jman774 (5)
(30 - Jul 06, 2013) Uncle Jeff (2)
(29 - Jul 05, 2013) garren (2)
(28 - Jul 04, 2013) jman774 (4)
(27 - Jul 03, 2013) GMD52
(26 - Jul 02, 2013) Red James cash (2)
(25 - Jul 01, 2013) Uncle Jeff (1)
(24 - Jun 30, 2013) Mackaydon (3)
(23 - Jun 29, 2013) Mackaydon (2)
(22 - Jun 28, 2013) andre1002 (2)
(21 - Jun 27, 2013) jman774 (3)
(20 - Jun 26, 2013) andre1002 (1)
(19 - Jun 25, 2013) Crispin (6)
(18 - Jun 24, 2013) jman774 (2)
(17 - Jun 23, 2013) pong12211
(16 - Jun 22, 2013) jman774 (1)
(15 - Jun 21, 2013) Crispin (5)
(14 - Jun 20, 2013) Crispin (4)
(13 - Jun 19, 2013) BrisJoe (3)
(12 - Jun 18, 2013) BrisJoe (2)
(11 - Jun 17, 2013) Crispin (3)
(10 - Jun 16, 2013) BrisJoe (1)
(09 - Jun 15, 2013) Mackaydon (1)
(08 - Jun 14, 2013) Crispin (2)
(07 - Jun 13, 2013) No Winner
(06 - Jun 12, 2013) garren (1)
(05 - Jun 11, 2013) Red James cash (1)
(04 - Jun 10, 2013) Backbacon
(03 - Jun 09, 2013) No Winner
(02 - Jun 08, 2013) frogginfish
(01 - Jun 07, 2013) Crispin (1)
(#) = Number of Wins

 

[GMD52]

VP, please correct me if I read everything wrong, but the math you did in the solution factered out to 10,330, making Uncle Jeff the winner, right?

 

[BryanM362]

9000 calories

Thats what I got too using proportions and cross multiplying.

 

[GMD52]

Bryan,

Looks like we went to the same math class.

 

[vpnavy]

VP, please correct me if I read everything wrong, but the math you did in the solution factered out to 10,330, making Uncle Jeff the winner, right?

Wow - sorry gang - blew that one big time - it has now been corrected!

 

[BryanM362]

Bryan,

Looks like we went to the same math class.

I think so, and it seems correct to me.

VP, can you elaborate on the solution, it doesn't make sense to me. Unless the weight and number of calories are not directly proportionate?

This is what I did:

X= number of calories for 420Kg steer needs.

630 420
----- X ----- = 630X = 420 x 13,500
13,500 X

630X = 5,670,000


5,670,000
x = ------------ = 9,000 calories
630


Thanks!


edit: Can't get the spaces to stay where I want them. Hopefully, you can figure out what I mean.