Nasreddin had a leaky ferry-boat, and used it to row people across the river. One day his passenger was a fussy schoolteacher, and on the way across he decided to give Nasreddin a test and see how much he knew.
"Tell me, Nasreddin, what are eight sixes?"
"I've no idea."
"How do you spell magnificence?"
"Didn't you study anything at school?"
"In that case, half your life is lost."
Just then a fierce storm blew up, and the boat began to sink.
"Tell me, schoolteacher," said Nasreddin. "Did you ever learn to swim?"
"In that case, your whole life is lost."