A letter of the word SECONDARY is selected at random. What is the probability that the letter selected is not a vowel?

Which of the following cannot be the probability of an event?

1. $\Big(\dfrac{3}{5}\Big)$

2. 25%

3. 0.96

4. −0.5

Which of the following cannot be the probability of an event?

1. $\Big(\dfrac{1.8}{3}\Big)$

2. $\Big(\dfrac{1}{0.4}\Big)$

3. $\Big(\dfrac{0.4}{5}\Big)$

4. $\Big(\dfrac{2}{65}\Big)$

If the probability of happening of an event is p, then the probability of it not happening is:

1. p

2. p − 1

3. 1 − p

4. $1 - \Big(\dfrac{1}{p}\Big)$