A person has four iron bars whose lengths are 24 m, 36 m, 48 m and 72 m respectively. This person wants to cut pieces of same length from each of four bars. What is the least number of total pieces if he is to cut without any wastage? Choices:
A) 11	B) 12	C) 15	D) 13	E) 17
15   15   24 = 12 × 2,   36 = 12 × 3,   48 = 12 × 4,   and 72 = 12 × 6   ∴ H15F (24, 36, 48, 72) = 12   Total pieces = 2 + 3 + 4 + 6= 
<gadget id="calculator">2 + 3 + 4 + 6</gadget>
<output>15</output>
15
<result>C</result>
A person has four iron bars whose lengths are 24 m, 36 m, 48 m and 72 m respectively. This person wants to cut pieces of same length from each of four bars. What is the least number of total pieces if he is to cut without any wastage?