Probability is the extent to which an event is likely to occur. It is the likelihood of sth to happen. In maths it is measured by the ratio of the favourable cases to the whole number of cases possible.
For instance there are 5 black balls and 2 white balls of same shape and size. If you picked one out of a bag it is more likely for you to pick a black one rather than a white one as it has more in number. So black balls have more probability.
And to find out probability of this above given event,
Sample space n(S) = 5+2 = 7 No. Of black balls n(B) = 5 No. Of white balls n(W) = 2
