Question 960454
There are 10 balls in the bag. 
3 balls are white.
5 balls are even.
No white balls are even.
The probabilities add.
{{{P(W)=3/10}}}
{{{P(even)=5/10}}}
{{{P(W_or_even)=3/10+5/10}}}
{{{P(W_or_even)=8/10=4/5}}}