题目询问 麻烦各位先进不吝指教

if a wire 27meters long is cut into three pieces of three different lengths, what is the length of the longest?

(1)the length of the longest piece is twice the length of the shortest piece

(2)the sum of the lengths of the two shorter pieces is 15 meters

答案给B

为什么D不行??

lz一定是误把长度也理解成为整数了，如果是整数，那么就是6，9，12；但如果不是整数，比如5.5，10.5，11 。。。