WAEC - Mathematics (2001 - No. 31)
If the probability that an event will occur is p and the probability that it will not occur is q, which of the following is true?
p-q=1
q-p=0
p+q=1
p+q=0
Forklaring
The probability that an event will certainly occur + the probability that an event will certainly not occur =
The probability that an event will certainly occur = 1 - the probability that an event will certainly not occur
The probability that an event will certainly not occur = 1 + The probability that an event will certainly occur
Option C is true.