Helping my friend

[Takari]

It's been 3 months since I did some simple Math.

Is this correct ?

hanna always eats one bowl of cereal for breakfast .
The probab. that she chooses muesli is 1/12 and the prob. that she chooses poridgeis 1/4.
work out the prob that she does not choose either of theses cereals .

5/12

[xKickAss]

Not sure if i understant, but it should be 8/12

[Alen]

This is pretty much the core of statistics/probability...

Anyways when you have mutually exclusive events (none of the events can happen at the same time ... e.g. she won't eat muesli and porridge at the same time) the probability of all the events should equal 1. A simple way to represent this with a diagram is this (sorry but I don't have my latex stuff set up so you'll have to live with paint):



tl;dr

P(muesli) + P(porridge) + P(everything else) = 1
P(everything else) = 1 - 1/12 - 1/4 = 2/3 (or 8/12 as xKickAss put it)

[Takari]

This is pretty much the core of statistics/probability...

Anyways when you have mutually exclusive events (none of the events can happen at the same time ... e.g. she won't eat muesli and porridge at the same time) the probability of all the events should equal 1. A simple way to represent this with a diagram is this (sorry but I don't have my latex stuff set up so you'll have to live with paint):



tl;dr

P(muesli) + P(porridge) + P(everything else) = 1
P(everything else) = 1 - 1/12 - 1/4 = 2/3 (or 8/12 as xKickAss put it)

I noticed .
I made a mistake but was lazy to edit it .