Question

A rectangular prism is 4 units by 2 1/2 units by 1 1/2 units. How many cubes with a side length of 1/2 unit will completely fill the prism ?

Answer 1

V prism = 4 × (5/2) × (3/2) = 15 units^3;
V cube = (1/2)^3 = 1/8 units^3;
15 ÷ (1/8) = 15 × 8 = 120 cubes;