Question

how did Private Quelch offend the Sergeant?

Answer 1

private quelch offended the sergeant by correcting and interrupting him in middle of a class . when the sergeant was explaining that the muzzle velocity of a bullet is over two thousand feet per second then the professor immediately interrupted saying that it is two thousand four hundred and forty feet per second . the sergeant was offended as he was corrected by his student in middle if the class .
after that when the sergeant started putting questions he turned with his questions again and again to professor (in hope of Revenge) . but only work they did was to enhance private quelch's glory.
hope this helps