To make soup away, Philip mixes 3 3/8 cups of broth with 2 1/4 cups of water. How many cups of liquid does he use?

To make soup, Philip uses a total of 3 3/8 + 2 1/4 = <<3+3/8+2+1/4=5 5/8>>5 5/8 cups of liquid. Answer: \boxed{5\frac{5}{8}}.