Seven boxes- B1, B2, B3, B4, B5, B6 and B7 are kept one above the other but not necessarily in the same order. The bottommost position is numbered as 1, above that 2 and so on.
Four boxes are kept between box B2 and box B6.
Box B2 is kept above box B6.
| Case 1 | Case 2 |
Position | Box | Box |
7 | B2 | |
6 | | B2 |
5 | | |
4 | | |
3 | | |
2 | B6 | |
1 | | B6 |
The number of boxes kept above box B2 is same as the number of boxes kept below box B4.
Box B4 is not kept at the bottommost position.
Thus, Case 1 gets cancelled.
| Case 2 |
Position | Box |
7 | |
6 | B2 |
5 | |
4 | |
3 | |
2 | B4 |
1 | B6 |
Two boxes are kept between box B1 and box B5.
Box B7 is kept immediately below box B1.
Position | Box |
7 | B5 |
6 | B2 |
5 | |
4 | B1 |
3 | B7 |
2 | B4 |
1 | B6 |
Now, box B3 is remaining.
Position | Box |
7 | B5 |
6 | B2 |
5 | B3 |
4 | B1 |
3 | B7 |
2 | B4 |
1 | B6 |
This is the final arrangement.
Box B3 is kept immediately above box B1 and immediately below box B2.