## ________________

A bit of calculation and reasoning is always good exercise for the team.

## ________________

### The Size of Humanity

Two years ago, the Earth’s population reached 7.4 billion people. Consider the Earth as a sphere of radius 6,371 kilometers and spread the volume of humanity over the surface of the Earth in a shell of constant thickness. Assume the average person occupies a volume of 63,000 centimeters3.

How thick would the shell be?

### Fish Pond

A fish pond has a horizontal bottom and vertical sides. To make a platform, the owner places three identical, impermeable cubical blocks side by side, resting on the bottom. The first block causes a rise in water level of less than 12 inches. The second and third blocks each cause the level to rise exactly 12 inches.

How high in inches is the water level above the top of the completed platform?

## Solutions to week 129

In Circumnavigation, the circumference can be no more than 500 miles. In Typos, the number of expected typos is 5,040.