Replace the question mark with a numberMATH PUZZLE: Can you replace the question mark with a number?
Three old men
Three old men are talking about their aches, pains and bodily dysfunctions.
One 75-year-old man says: "I have this problem. I wake up every morning at 7 a.m. and it takes me 20 minutes to pee."
An 80-year-old man says: "My case is worse. I get up at 8 a.m. and I sit there and grunt and groan for half an hour before I finally have a bowel movement."
The 90-year-old man says: "Not me. At 7 a.m. I pee like a horse and at 8 a.m. I crap like a cow."
"So what's your problem?" asked the others.
"I don't wake up until 9:00."