A traveller came upon an old farmer hoeing in his field beside the road. He called out to the farmer, who looked up from his work.

"How long will it take me to walk to the next town?" he asked.

"Can't tell you," was the farmer's curt reply.

Feeling insulted at this, the traveller walked away.

"About an hour," shouted the farmer after him.

"Why didn't you say so when I first asked?"

"Because I didn't know how fast you were walking."