I am questioning the supposedly given correct answer for an H-NMR question. I am also wondering if this question is reasonable to solve in some way without a chemical shift additivity calculation, or perhaps even better, 2-D NMR. Supposedly, the correct answer can be reached without knowledge of either of these things (only 1-D NMR was provided, and the student has not been taught about chemical shift additivity).
I attached a picture of two different constitutional isomers that are consistent with all of the splitting and integration, and most of the chemical shift data. The question lies with the connectivity of the propyl group and methyl group. The propyl group could be bonded to the aromatic ring and the methyl could be bonded to the ketone carbonyl, or vice versa.
I did a quick additivity calculation and it appears the aryl substituent will have a higher PPM. This is consistent with the data, but I am wondering how we are supposed to know this without precise knowledge of chemical shift values, given that the two PPM's are so close.