The probability that an event happens is 0.42. What is the probability that the event won't happen?

Solution:

The probability of an event happening is = 0.42 .i.e.

p(event Happening) = 0.42

p(event not happening) = 1 - p(event happening)

= 1 - 0.42

= 0.58

The event not happening is actually called the complement of the event happening.

Example:

If we throw a dice what is the probability that the number appearing will be at least 2:

This probability implies the sum of the following probabilities i.e.

p(2) + p(3) + p(4) + p(5) + p(6)

Instead of finding the five probabilities it is better to find the probability of not getting one on the roll of a dice.

p(not getting one on roll of dice) = 1 - p(getting one on roll of dice)

= p(2) + p(3) + p(4) + p(5) + p(6)

Therefore,

p(not getting one on roll of dice) = 1 - p(getting one on roll of dice)

= 1 - 1/6

= 5/6

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The probability that an event happens is 0.42. What is the probability that the event won't happen?

Summary:

The probability that an event happens is 0.42. The probability that the event won't happen is 1 - 0.42 = 0.58