Answer and prove you know many tricks?

Question

Is there any easiest way to solve probability problem than draw tree diagram?

give a example

Answer 1

to calculate just time the total of first choice and the total of second choice or until the total of n choice.
or you can try this: if you toss n coins total probability is 2^n
if you toss n dice total probability is 6^n

or if you wanna know the probability just arrange it and try this
ex: the probability if you take two alfabets from A - I are
AA,AB,AC,ETC
BA,BB,BC,ETC
ETC

: )

Answer 2

if the tree has the same branchfactor in each node then yes, otherwise probably not.

Answer 3

you take the number of choices for the first variable and times it buy the number of of choices for the second and so on and that will give you the number of possible combos.