Answer:
67%
Step-by-step explanation:
First We will calculate Dow Jones Industrial Average Decrease
Industrial Average in October 1929 = 300
Industrial Average in October 1931 = 100
So the decrease in Industrial Average is (300-100) = 200
Now We will calculate the Industrial Average decrease in percent
(200/300) x 100 = 66.66%
Rounded to 67%