January 11, 2003

One Hundred Interesting Mathematical Calculations, Number 6

**One Hundred Interesting Mathematical Calculations, Number 6: How Much Blood Is There in the World? **

Begin with the fact that there are six billion people in the world, each of whom has about a gallon of blood. A gallon is about 0.133 cubic feet. So multiply 6 x 10^{9} x 0.133 = 8 x 10^{8} cubic feet of blood.

How much blood is this? The cube root of 8 x 10^{8} is 928. All the human blood in the world could be stuffed into a cube less than one-thousand feet on a side.

From John Allen Paulos's *Innumeracy.*

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That's a surprising result, indeed. I would have made a much larger guess off the top of my head.

Posted by: Jean-Philippe Stijns on January 13, 2003 11:02 AMPost a comment