Box Name: Blue, Black, White, Red, GREEN, Orange, Yellow

Number of Articles: 8, 4, 7, 19, 15, 14 and 20

1) There are two BOXES between a Red coloured box and the box in which 19 articles are present.

2) Red coloured box is placed above the box that has 19 articles.

3) Red coloured box is placed below Blue coloured box.

4) There are two boxes between a Blue coloured box and the one having 7 articles.

5) There are only three boxes between Green coloured box and the box having 7 articles.

6) Box containing 7 articles are not in the bottom two places.

7) An orange coloured box is IMMEDIATELY below the box having 15 articles.

8) Blue coloured box doesn’t have 15 articles. 

9) There are two boxes between the boxes having 15 and 4 articles.

10) There is only one box between Black and Yellow coloured box.

11) A white coloured box is not the bottom-most box.

(Here case 1.1, 1.2 and 2.1 gets eliminated)

12) The DIFFERENCE between the number of articles in box Red coloured and the one just above Red is the perfect square is not a square of a prime number.

(As just above Red there are 4 article so Red is to have 20 article)

(Now Difference = 20 – 4= 16 = 42)

13) A black coloured box does not have 4 number of articles.

(Therefore Black will be having 7 article)

14) The number of articles in the box which is just above Yellow coloured box is multiple of the number of articles in Yellow coloured box.

(Now only 14 and 8 articles are left therefore just above Yellow there will be 8 article)