P1) Q lives on an even-numbered floor but not on the 4th floor.2) Q lives just below the floor of R, whose age is 5 years. Floor PERSON Age 6 5 4 3 R 5 years 2 Q 1 3) Only TWO PEOPLE live between the floors on which Q and U live.4) The one whose age is 10 years lives below Q. 5) The one whose age is 20 years lives on the topmost floor. Floor Person Age 6 20 years 5 4 3 R 5 years 2 Q 1 10 years 6) Only two people live between the floors on which Q and U live. S does not live on an odd-numbered floor.7) S lives on a floor between U and Q and his age is 15 years. Floor Person Age 6 20 years 5 U 4 S 15 years 3 R 5 years 2 Q 1 10 years 8) U is 5 years elder than P. 9) T does not live on the topmost floor. Therefore, P lives on the topmost floor, as U is 5 years elder than P, so U's age is 25 years. Floor Person Age 6 P 20 years 5 U 25 years 4 S 15 years 3 R 5 years 2 Q 1 T 10 years The one who lives just above T is 3 years elder than T. Floor Person Age 6 P 20 years 5 U 25 years 4 S 15 years 3 R 5 years 2 Q 13 years 1 T 10 years Hence, U lives on floor number 5.