Directions: Read the given instructions and answer the following questions:

Four boxes A, B, C and D are placed one above the other. One box is placed between A and C. A is adjacent to D.

If P is added to this stack, above C below A and Q is placed just above D. All boxes contain different number of pencils in consecutive multiple of 6 from bottom to top. A contains 30 pencils. B is not placed at the top.