The Street's Jim Cramer answered viewers' Twitter questions from the floor of the New York Stock Exchange, where he addressed China's currency devaluation, Shake Shack, some health companies, and Qorvo. Jim's first question was whether China's devaluation of the yuan would temper the Fed's desire to raise rates. Jim responded, 'If it's calm and they don't devalue again, then they will raise rates.' On Thursday, U.S. stocks largely shook off the devaluation, rebounding from Wednesday's decline. Jim was asked by one viewer about whether it was a good idea to buy shares of Shake Shack (SHAK),and he responded it's only a good idea if you want to wait for a four or five year period. Jim said the stock is 'hideously overvalued' compared to other names he follows like Red Robin (RRGB) and Jack in the Box (JACK). Send your questions to @JimCramer, with #CramerQ.