Physics help with tuning forks?

Two tuning forks are sounded at the same time. One tuning fork has a known frequency of 256 hertz. When the two tuning forks are sounded together, a beat frequency of 5 hertz is heard. What is/are the possible frequency/frequencies of the second tuning fork? Are you supposed to make two frequency equations equal each other? f = 1/T? I'm not sure how to do this problem.