How many boxes are placed above B?

Solution

Only two boxes are kept between D and G where G is placed above D. Only one person sits between E and D. Here we get two cases, Case 1 and Case 2. Case-1                               case-2 Box F is three places above G. No box is placed above F. Only three boxes are placed between A and I, and A is not an immediate neighbor of D. H is placed immediately above E. Box C is kept at third position either from top or bottom. Here Case 1 gets eliminated and the final arrangement is,