Sometimes ordinary people have to invent something for their households. They do this for different reasons. What did Mr Frank B. Gilbreth invent? Why did he do that? (reading for specific information)

Mr Gilbreth invented process charts first developed for industry to be used in the household. He did it to make household efficient. (Мистер Гибрет придумал использовать графики, изначально разработанные для производства, в домашнем хозяйстве).