Question

draw structure of 2,3,5-tri methyl -4-propyl heptane explain why is not written as 3-ethyl -4- (1-methyl propyl) heptane

Answer 1

NO it can't be written that way since then the two compounds become isomers. Because the number of atoms in the substitute chain will differ causing difference in chemical and physical differences.
I guess it's the right answer..