How many persons live between B and

Solution

Only two persons live below the floor on which H lives. Only one person lives between H and X. X does not live on the lowermost floor. Using the above information we can place X and H on the floor number 5 and 3 respectively. U lives on an odd numbered floor but not on floor number 7. Only two persons live between U and Y. Y does not live on the topmost floor. We can use the above information to place U and Y in the table as shown below. B lives immediately below Z. Neither B nor C lives on floor number 6. After using the above information we can place B, Z and C in the table and here we can see that there is only spot left on the table which will be filled by last remaining member i.e. D.