The width of the rectangular parallelepiped is 15 dm, the length is 3 dm more

The width of the rectangular parallelepiped is 15 dm, the length is 3 dm more than the width, and the height is 3 times less than the length. Find the volume of this box.

The task:
parallelepiped width b – 15 dm,
length a -? dm, 3 dm more than width,
height c -? dm, 3 times less than the length,
volume V -? dm ^ 3.
1) find the length a of the parallelepiped:
a = 15 + 3 = 18 dm;
2) define the height with:
c = a: 3 = 18: 3 = 6 dm;
3) calculate the volume of the parallelepiped:
V = a b c = 18 15 6 = 1620 dm ^ 3.
Answer: V = 1620 dm ^ 3.