There is a cube of height H, and there are 4 moving particles on the vertical edges of the cube. Initially particles are at some height A, B, C and

D respectively. These particles are moving in different direction (Only upward or downward, no sideways movement) with different speed.

If the particle is moving upward or downward reaches the tip of the cube then it remain at the tip only and will not move further. If other particles

have not reach the tip they continue to move along their respective edges in their respective direction till the last particle reaches the tip.

These 4 particles will make two triangles in a 3-D plane. Since the particles are moving, sum of the area of these two triangles will change

every moment.

Find out the maximum and minimum of the sum of the areas of these two triangles.

Refer the Examples section for better understanding.