# Math

posted by
**Karen**
.

How do you weight probabilities to add up to 1?

Example:

Chance of rain .25

Chance of person wearing purple hat .1

Chance of person wearing red hat .05

Chance of person wearing black hat .2

Chance of person wearing yellow hat .1

Chance of person wearing white hat .3

So, You run into a person wearing a hat in the rain.

The chance of running into people in each color of hat in the rain is

Chance of person wearing purple hat .025

Chance of person wearing red hat .0125

Chance of person wearing black hat .05

Chance of person wearing yellow hat .025

Chance of person wearing white hat .075

Would I weight this to make it all add up to 1? What is what I need to do called?