Excel 97: Find a Value Less Than Another in Array

I have a two column array of 30 rows.

Each cell in Column A contains a sequential value from 61 – 90 (person’s age).

Each cell in column B contains a decreasing value that eventually goes negative (retirement savings being run down). The starting value in the first row of column B can vary, which means that the cell in Column B that goes negative can change.

I want to be able to find the value for the cell in Column A alongside the same row that the cell in column B goes negative.

I have attempted to use VLOOKUP but seem unable to use a ‘less than zero’ value.

Your assistance will be appreciated.