how do i work out probabilities?

Answer 1

For discrete events, the basic procedure is to list all possible outcomes, and the probability of each (which must add up to 1). The probability of being in one of an identifiable smaller group of outcomes (called a subset) is simply the sum of the individual probabilities of the outcomes within that group.

For example, if you have two distinguishable dice, there are 36 different ways they can be rolled. If the dice are unweighted, the probability of each is 1/36. Of those, 6 add up to 7. That means the odds of getting 7 are 6/36=1/6.

Answer 2

While calculating the probabilities is a subject of a whole branch of mathematics, and often can be very complex, in many cases you can calculate the probability of the event by comparing the number of outcomes that lead to this even to the number of all possible outcomes. For example, if you throw a dice, there are 6 possible outcomes and only one of them leads to getting, for example, 5. So the probability of getting 5 would be 1/6.

Answer 3

probablities of what?

if its heads or tails its 1/2 - or 0.50

if its a "three sided coin (hehe)" it would be a 1/3 which is 0.33

are you getting this???

1 in five it will be 0.20