Product of the simple events is the probability of a compound event.
Occurrence of more than one event simultaneously or one after another is called a compound event. In such cases we have to find the probability of simple events. The Product of such simple events is called the probability of a compound event.
For example we shall conduct a random experiment of tossing a single coin twice. To find the probability of head on the first toss and tail on the second toss, we have to calculate
P(h) on the first toss [This is a simple event]
We have to calculate the probability of tail on the second toss
P(t) on the second toss.[Again this is a probability of a simple event]
[Head on the first toss and tail on the second toss is a compound event] hence,
P(h) ##xx##P(t) is the probability of the required event.