How to solve the following problems? How to analyze it?

The person in front of him accounts for 3/2 of the total number, which should be 2/3.

Xiao Ming is1-2/3-1/4 =1-8/12 =12.

That is, Xiaoming accounts for112 of the total population, and the total population is12.

There are 12*(2/3)=8 people in front of Xiao Ming, so Xiao Ming ranks ninth.