Conditional Probability

[Blood Angel]

Hi,

In layman’s terms, can someone please explain to me how to work this out.
I have googled it but it’s unclear to me   

Thank you. 
BA

[Herby]

I throw a dice, you don't see it but have to guess the outcome:
What's the probability its a 6 ?   1/6

If I tell you the outcome is even:  What's the probability its a 6 ?   

1/3 because there are only 3 even numbers (2, 4, 6) left.
The info that the outcome is even is here the condition.   

[Blood Angel]

I throw a dice, you don't see it but have to guess the outcome:
What's the probability its a 6 ?   1/6

If I tell you the outcome is even:  What's the probability its a 6 ?   

1/3 because there are only 3 even numbers (2, 4, 6) left.
The info that the outcome is even is here the condition.   

Thank you Herby.