The user-friendly version of this content is available here.

The following content is copyright (c) 2009-2013 by Goods of the Mind, LLC.

This problem trains for: SAT-I.

A coin is dropped at random within this contour:

Ignore the fact that the coin has dimensions.

What is the probability for the coin to land 'head' on black?

The event 'land head on black' is a compound event formed by two elementary independent events:

- land with the 'head' side upwards
- fall within the black areas

The probability of the event is the product of the probabilities of the two independent events: