Which of the following numbers represent the probability of an event that is less likely to occur than not occur?

1/5

1/2

0.25

0.75

Well,

The probability that is least likely to occur is the smallest probability.

0.2

0.5

0.25

0.75

0.2, or 1/5, is the smallest number and therefore the probability which is the least likely to occur.

Converting them all to decimals you end up with:

0.2

0.5

0.25

0.75

so it would be 1/5, if I understand the question right