I, J, K, L, Y, and Z live on six different floors of the same building. The lowermost floor in the building is numbered 1, the floor above it is numbered 2, and so on till the topmost floor is numbered 6. I lives on floor numbered 5. L lives on a floor above
I. Only K lives below Y. Z lives on an even-numbered floor. How many people live below J?  

1.    I lives on floor 5.
→ So, I = 5 2.    L lives on a floor above I.
→ So, L can be on floor 6 only (since floor 5 is already taken by I) 3.    Only K lives below Y.
→ This means: o    K is the only person living on a floor lower than Y o    So, Y must be higher than K, and everyone else must be either above Y or between Y and K 4.    Z lives on an even-numbered floor.
→ So Z can be on floor 2 , 4 , or 6
→ But L is already on 6 (from clue 2), so Z can be on 2 or 4 ·    From clue 1 and 2: o   I = 5 , L = 6 ·    Assume K is on floor 1 (lowest possible) ·    Since only K lives below Y, that means Y must be on floor 2 So: K = 1 , Y = 2 ·    That leaves floors 3 and 4 (and Z must be on an even floor).
So Z must be on floor 4
Z = 4 ·    We now only have floor 3 left for J
J = 3 Final arrangemnt: How many people live below J? •  People below J are: Y (floor 2) and K (floor 1) •  So, 2 people live below J