Naming incorrect compounds
Each of the following names is an incorrect IUPAC name. Indicate, if possible, the correct name of the compound. can you please explain why these names are not right. I do not understan. These are the 3 I can not figure out.
1) 4-butyl 1-methyl 2-hexene
2) 2-ethylpentane
3)1-propyl 5-methyl benzene