# Monthly Archives: January 2014

## How many gallons of human blood are there?

For this we need to know how many people there are and the average amount of blood in each one. Unfortunately, I will be assuming that all humans are adult sized with an adult amount of blood, which I’m fairly sure is not the case, so the estimated value will be higher than the actual value by a fairly substantial amount.
Now then. As of January 3rd, 2014, the date which this was written, the Worldometers world population clock [1] put the total world population at about 7.204 billion people.
As for blood, hypertextbook [2] cites several scientific studies which have found that the amount of blood in the average adult is right around 5 liters (or about 5 quarts). This means that the average person has about 1.25 gallons of blood.
By multiplying the two results we find that the total amount of human blood is right around 9 billion gallons.
Using data from a 2010 Pew poll of world religions [3] we find that there are 2.8 billion gallons of Christian blood, 2.1 billion gallons of Muslim blood, 1.4 gallons of Hindu blood and only 18 million gallons of Jewish blood. (These numbers don’t add up to the total because of other religions and the 1.5 gallons of unaffiliated blood)

Filed under Biology, Mathematics, Religion

## How rich do I have to be in order to fill an Olympic swimming pool with pennies?

We need to know a few things for this answer, the volume of an Olympic swimming pool and the volume of the penny (US coin).

First of all, the FINA lists the dimensions of an Olympic swimming pool as such:

50 meters long by 25 meters wide by at least 2.0 meters deep [1]

Since the depth could conceivably be unlimited, we will use a depth of 2.0 meters, meaning that the total volume of an Olympic swimming pool is 2,500 cubic meters.

The US Mint gives the following specifications for a penny:

A diameter of 19.05 millimeters and a thickness of 1.52 millimeters [2]

This means that the US penny has a volume of 4.3323E-7 cubic meters

Using these results, we find that 5.771 billion pennies are needed to fill the pool, which all together are worth 57.7 million US dollars.

One more thing:

Forbes lists the worlds billionaires here, the richest people on Earth. Currently, Carlos Slim Helu and his family are listed at #1 with a net worth of about 73 billion US dollars. [3]

If they so desired, they could fill over 1200 Olympic swimming pools with pennies. So yeah.