Five children A, B, C, D, and E live in the same building. The number of floors that A lives in is twice that of B, three times that of C, four times that of D, and six times that of E. It is known that C is just right. Live on the upper floor of D, then how many floors does B live on?
A、B、C、D、E五个小朋友住在同一栋楼里，A住的楼层数是B的2倍，C的3倍，D的4倍，E的6倍，又已知C正好住在D的楼上，那么B住在多少层．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<result>6</result>