Ask someone to help me look at the solution of a probability problem in mathematics (compulsory 3 in senior high school mathematics): ~ ~ ~ ~ ~ ~

(1), draw a circle first, you can paint it red or blue, then draw a triangle, and then draw a rectangle, which is also two results. All the results are equivalent to throwing a coin three times in a row. There are eight basic situations for all results, namely

Round red, three blues, long blue, round blue, three reds, long blue, round blue, three blues, long blue.

Round red, three blues, long red, round blue, three reds, long red, three reds, long blue, round red, three reds, long red.

It's not easy to draw this tree by yourself.

(2)p( 1)= 1/8

p(2)=4/8= 1/2

p(3)=4/8= 1/2

p(4)=6/8=3/4