Conversation so far:
What was John J. Pershing's first job
John J. Pershing reported for active duty on September 30, 1886, and was assigned to Troop L of the 6th U.S. Cavalry.
How did John J. Pershing get into the job in the U.S. cavalry
John J. Pershing was sworn in as a West Point cadet in the fall of 1882. He was selected early for leadership positions.

Question: How long was he with the U.S Cavalry
Self-contained rewrite: How long was John J. Pershing with the U.S Cavalry