Genesis 40:18

And Joseph answered and said, This is the interpretation thereof: The three baskets are three days:

Cross-reference

In Genesis 40:12, Joseph interprets the cupbearer's dream with the same formula: three items = three days — paralleling his interpretation here.

In Genesis 41:26, Joseph again interprets symbolic numbers as time (seven cows = seven years), echoing his method of three baskets = three days here.