Mathematics for IGCSE & O level - Probability (Section 6 - No. 46)
If the probability of an event occurring is 3/5, what is the probability that the event will *not* occur?
2/5
3/5
1/5
4/5
Explication
Probability of not occurring is 1 - the probability of occurring. 1 - 3/5 = 2/5.