Question

How do I do probability and compunds

Answer 1

The probability is how likely an event is to happen.

Many events can't be predicted with total certainty. The best we can hope is to say how likely they are to happen.

Think on the following problem: When a coin is tossed we have to possible outcomes, heads or tails. Since we only have two possible outcomes we say that the proability of obtaining a head is 1/2 and the probability of obtaining a tail is also 1/2. Hence we have a 50% likelihood of obtaining one of the possibilities.

Another example is a dice. In this case we have 6 possible outcomes, then the probability of each of them is 1/6, that is, we have a chance out of six of obtaining one of the possible outcomes.

In general the proability that an event A happens is:

`P(A)=\frac{\text{ number of favourable outcomes}}{Total\text{ number of outcomes}}`

Example:

There are 6 pillows in a bed, 3 are red, 2 are yellow and 1 is blue. What is the probability of picking a yellow pillow?

Since we have 6 pillows and only 2 of them are yellows, the probability of picking one of them is:

`P=(2)/(6)=(1)/(3)`

Therefore we have a 33.33% chance to pick a yellow pillow.