Question:
If the probability of winning a game is 0.3, what is the probability of loosing it?
Solution:
Given: Probability of winning a game 
TO FIND: Probability of losing the game 
CALCULATION: We know that sum of probability of occurrence of an event and probability of non occurrence of an event is 1.
$P(E)+P(\bar{E})=1$
$0.3+P(\bar{E})=1$
$P(\bar{E})=1-0.3$
$P(\bar{E})=0.7$
Hence the probability of losing the game is $P(\bar{E})=0.7$