Ok, so this is a similar problem to the previous question. Whenever there is an "of" after a value, it means multiply. As seen in this problem, it says 1/10 Of the space. "The space" refers to the 4,000 square feet.
4,000 * 1/10 = 4,000/10 = 400
Your bakery is 400 square feet.
Hope this helps!