cis-1-tert-butyl-3-methylcyclohexane will have a higher percentage of the diequatorial-substituted conformer when compared with the diaxialsubstituted conformer.
Explanation:
The two compound contain or have high stability with the substituent group is at equatorial position but the tert-betyl group in cis-1-tert-butyl-3-methylcyclohexane is larger than the methyl group in trans-1,4-dimethylcyclohexane.
Thus, the equatorial position will be more favorable for the substituent group in the cis-1-tert-butyl-3-methylcyclohexane, therefore having higher percentage of the diequatorial substituted conformer compared with that of diaxial-substituted conformer.