On the first day of training for parachute jumping, a blonde listened intently to the instructor.
He told them to start preparing for landing when they are at 300 feet.
The blonde asked, "How am I supposed to know when I'm at 300 feet?"
"That's a good question. When you get to 300 feet, you can recognise the faces of people on the ground."
After pondering his answer, she asked,