"A gallon of cow's milk," he said to the milkman.
"I'm sorry, Nasruddin," the milkman replied, "but the container you've brought is much too small. There's no way a gallon of cow's milk will fit into that container."
Nasruddin stood there thinking.
"I know!" he said at last. "Instead of a gallon of cow's milk, give me a gallon of goat's milk. Goat's milk will be just the right size!"
Inspired by: Classic Tales of Mulla Nasreddin retold by Houman Farzad, and translated by Diane Wilcox
Notes: This story is on p. 30 of the book.