In the same article, in the section, "rush of sales increases", the stock market crash of 1929 took place approximately how long after the market had established new record high price levels?

just over two months

Explanation:

The Crash of the New York Stock Exchange in 1929 marks the beginning of the greatest economic crisis in history, which began the financial system, affecting the price of stocks, and quickly spread. The US economy was experiencing a boom in the 1920s, with sudden increases in sales, leading to overproduction and unrestrained credit growth. This euphoria took the value of NYSE-traded securities to such high levels that in just over two months the fateful black Thursday, the day the NY stock traded, broke out. Without demand for the securities, stock and bond prices plummeted, generating a great wave of mistrust, and producing a chain reaction in the other sectors of the economy. It was the beginning of the crisis that led to the Great Depression.

a little more than two months