Final answer:
The correct journal entry to record Sam Singh's $90,000 investment for a 1/3 interest in a partnership is to debit Cash and credit Sam Singh, Capital, both for $90,000.
Step-by-step explanation:
The correct journal entry to record Sam Singh's investment in a newly formed partnership where he invested $90,000 cash for a 1/3 interest is: Debit Cash $90,000; Credit Sam Singh, Capital $90,000.
This reflects an increase in the partnership's cash account and acknowledges Sam Singh's contribution to the partnership's capital.