In order to prepare for the operation test of physical chemistry experiment in senior three, a school conducted simulation training for senior three students. There were four different operation exper

In order to prepare for the operation test of physical chemistry experiment in senior three, a school conducted simulation training for senior three students. There were four different operation experiments in physical chemistry. ( 1) (2)

Test and analysis: (1) Draw a tree diagram:

As shown in the figure, there are 16 possibilities for a classmate to draw lots;

(2)∵ Xiao Zhang draws two better experimental questions prepared by the subjects at the same time in four situations: 1B, 1C, 2B and 2C * * *.

What is the probability that he will draw out two carefully prepared experimental questions at the same time?

Comments: This question examines drawing a tree diagram and probability; Ask candidates to draw a tree diagram and calculate the probability.