10.
E, F, G, H, I and J live on six different floors of the same building. The lowermost floor in the building is numbered 1, the floor above it number 2, and so on till the topmost floor is numbered 6.
G lives on the lowermost floor. Only J lives between the floors occupied by H and I. E lives on floor number 2. F lives on an even numbered floor, with I as an immediate neighbour. Who lives on floor number 4?