Mathematics for IGCSE & O level - Probability (Section 3 - No. 19)
If the probability of an event happening is 0.2, what is the probability of the event *not* happening?
0.2
0.4
0.8
1.0
คำอธิบาย
The probability of not happening = 1 - Probability of happening = 1-0.2 = 0.8