Six friends namely –P, Q, R, S, T and U lives in six

Solution

We have: R, who lives on odd numbered floor but not on floor marked 3, lives just above one who likes White, that means R lives on floor marked 5. Only two person lives between S and one who likes White, that means S lives on floor marked 1. T, who likes Blue, neither lives adjacent floor of S nor on adjacent floor of R, that means T lives on floor marked 3.  One who likes Black lives on topmost floor. Based on above given information we have: From I We have:  U, who neither likes Black nor likes White, lives at a gap of two floor from one who likes Red, that means U lives on floor marked 2.  Only two person lives between Q and one who likes Green, that means Q likes White. Based on above given information we have: Clearly, four person lives above one who likes Yellow Hence, statement I is alone sufficient. From II: We have:  Q, who lives on adjacent floor of one who likes Blue, lives at a gap of two floor from one who likes Green. U, who doesn’t lives of top floor, lives just above floor of one who likes Green, that means U lives on floor marked 2. Based on above given information we have:  Clearly, we don’t know exact person one who likes Yellow. Hence, statement II is not sufficient.