Three elderly sisters shared a house together.

One evening, the eldest sister went upstairs to take a bath. As she put her foot into the tub, she paused.

“Was I getting in the tub or out?” she yelled to her sisters.

“You old fool,” said the middle sister. “I’ll come up and see.”

When she got halfway up the stairs, she paused.

“Was I going up the stairs or down?” she yelled to her sisters.

The youngest sister was sitting at the kitchen table drinking a cup of tea.

“I hope I never get that forgetful, knock on wood,” she said.

Then she called out to her sister, “I’ll be up to help you both as soon as I see who’s at the door.”